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‎.gitattributes

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# Auto detect text files and perform LF normalization
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* text=auto

‎README.md

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# Shortest-Path-Algo

‎Summary.docx

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Binary file not shown.

‎astar.cpp

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#include<bits/stdc++.h>
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#define ROW 9
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#define COL 10
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using namespace std;
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typedef pair<int, int> Pair;
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typedef pair<double, pair<int, int> > pPair;
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int arr[ROW][COL]={0};
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struct cell{
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int parent_i, parent_j;
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double f, g, h;
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};
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bool isValid(int row, int col){
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return (row >= 0) && (row < ROW) &&
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(col >= 0) && (col < COL);
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}
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bool isUnBlocked(int grid[][COL], int row, int col){
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if (grid[row][col] == 1)
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return (true);
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else
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return (false);
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}
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bool isDestination(int row, int col, Pair dest){
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if (row == dest.first && col == dest.second)
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return (true);
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else
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return (false);
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}
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double calculateHValue(int row, int col, Pair dest){
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return ((double)sqrt ((row-dest.first)*(row-dest.first)
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+ (col-dest.second)*(col-dest.second)));
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}
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void tracePath(cell cellDetails[][COL], Pair dest){
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printf ("\nThe Path is ");
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int row = dest.first;
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int col = dest.second;
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stack<Pair> Path;
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while (!(cellDetails[row][col].parent_i == row
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&& cellDetails[row][col].parent_j == col ))
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{
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Path.push (make_pair (row, col));
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int temp_row = cellDetails[row][col].parent_i;
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int temp_col = cellDetails[row][col].parent_j;
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row = temp_row;
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col = temp_col;
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}
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Path.push (make_pair (row, col));
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while (!Path.empty()){
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pair<int,int> p = Path.top();
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Path.pop();
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printf("-> (%d,%d) ",p.first,p.second);
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arr[p.first][p.second]=99;
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}cout<<endl;
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return;
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}
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void aStarSearch(int grid[][COL], Pair src, Pair dest){
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if (isValid (src.first, src.second) == false){
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printf ("Source is invalid\n");
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return;
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}
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if (isValid (dest.first, dest.second) == false){
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printf ("Destination is invalid\n");
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return;
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}
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if (isUnBlocked(grid, src.first, src.second) == false ||
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isUnBlocked(grid, dest.first, dest.second) == false)
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{
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printf ("Source or the destination is blocked\n");
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return;
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}
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if (isDestination(src.first, src.second, dest) == true){
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printf ("We are already at the destination\n");
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return;
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}
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bool closedList[ROW][COL];
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memset(closedList, false, sizeof (closedList));
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cell cellDetails[ROW][COL];
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int i, j;
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for (i=0; i<ROW; i++){
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for (j=0; j<COL; j++){
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cellDetails[i][j].f = FLT_MAX;
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cellDetails[i][j].g = FLT_MAX;
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cellDetails[i][j].h = FLT_MAX;
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cellDetails[i][j].parent_i = -1;
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cellDetails[i][j].parent_j = -1;
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}
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}
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i = src.first, j = src.second;
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cellDetails[i][j].f = 0.0;
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cellDetails[i][j].g = 0.0;
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cellDetails[i][j].h = 0.0;
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cellDetails[i][j].parent_i = i;
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cellDetails[i][j].parent_j = j;
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set<pPair> openList;
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openList.insert(make_pair (0.0, make_pair (i, j)));
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bool foundDest = false;
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while (!openList.empty()){
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pPair p = *openList.begin();
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openList.erase(openList.begin());
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i = p.second.first;
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j = p.second.second;
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closedList[i][j] = true;
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double gNew, hNew, fNew;
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if (isValid(i-1, j) == true){
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if (isDestination(i-1, j, dest) == true){
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cellDetails[i-1][j].parent_i = i;
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cellDetails[i-1][j].parent_j = j;
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tracePath (cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i-1][j] == false &&
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isUnBlocked(grid, i-1, j) == true)
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{
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gNew = cellDetails[i][j].g + 1.0;
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hNew = calculateHValue (i-1, j, dest);
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fNew = gNew + hNew;
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if (cellDetails[i-1][j].f == FLT_MAX ||
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cellDetails[i-1][j].f > fNew)
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{
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openList.insert( make_pair(fNew,
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make_pair(i-1, j)));
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cellDetails[i-1][j].f = fNew;
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cellDetails[i-1][j].g = gNew;
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cellDetails[i-1][j].h = hNew;
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cellDetails[i-1][j].parent_i = i;
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cellDetails[i-1][j].parent_j = j;
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}
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}
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}
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if (isValid(i+1, j) == true){
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if (isDestination(i+1, j, dest) == true){
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cellDetails[i+1][j].parent_i = i;
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cellDetails[i+1][j].parent_j = j;
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tracePath(cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i+1][j] == false &&
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isUnBlocked(grid, i+1, j) == true)
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{
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gNew = cellDetails[i][j].g + 1.0;
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hNew = calculateHValue(i+1, j, dest);
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fNew = gNew + hNew;
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if (cellDetails[i+1][j].f == FLT_MAX ||
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cellDetails[i+1][j].f > fNew)
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{
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openList.insert( make_pair (fNew, make_pair (i+1, j)));
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cellDetails[i+1][j].f = fNew;
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cellDetails[i+1][j].g = gNew;
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cellDetails[i+1][j].h = hNew;
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cellDetails[i+1][j].parent_i = i;
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cellDetails[i+1][j].parent_j = j;
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}
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}
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}
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if (isValid (i, j+1) == true){
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if (isDestination(i, j+1, dest) == true){
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cellDetails[i][j+1].parent_i = i;
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cellDetails[i][j+1].parent_j = j;
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tracePath(cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i][j+1] == false &&
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isUnBlocked (grid, i, j+1) == true)
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{
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gNew = cellDetails[i][j].g + 1.0;
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hNew = calculateHValue (i, j+1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i][j+1].f == FLT_MAX ||
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cellDetails[i][j+1].f > fNew)
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{
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openList.insert( make_pair(fNew,
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make_pair (i, j+1)));
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cellDetails[i][j+1].f = fNew;
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cellDetails[i][j+1].g = gNew;
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cellDetails[i][j+1].h = hNew;
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cellDetails[i][j+1].parent_i = i;
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cellDetails[i][j+1].parent_j = j;
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}
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}
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}
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if (isValid(i, j-1) == true){
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if (isDestination(i, j-1, dest) == true){
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cellDetails[i][j-1].parent_i = i;
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cellDetails[i][j-1].parent_j = j;
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tracePath(cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i][j-1] == false &&
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isUnBlocked(grid, i, j-1) == true)
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{
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gNew = cellDetails[i][j].g + 1.0;
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hNew = calculateHValue(i, j-1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i][j-1].f == FLT_MAX ||
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cellDetails[i][j-1].f > fNew)
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{
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openList.insert( make_pair (fNew,
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make_pair (i, j-1)));
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cellDetails[i][j-1].f = fNew;
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cellDetails[i][j-1].g = gNew;
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cellDetails[i][j-1].h = hNew;
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cellDetails[i][j-1].parent_i = i;
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cellDetails[i][j-1].parent_j = j;
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}
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}
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}
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if (isValid(i-1, j+1) == true){
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if (isDestination(i-1, j+1, dest) == true){
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cellDetails[i-1][j+1].parent_i = i;
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cellDetails[i-1][j+1].parent_j = j;
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tracePath (cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i-1][j+1] == false &&
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isUnBlocked(grid, i-1, j+1) == true)
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{
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gNew = cellDetails[i][j].g + 1.414;
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hNew = calculateHValue(i-1, j+1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i-1][j+1].f == FLT_MAX ||
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cellDetails[i-1][j+1].f > fNew)
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{
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openList.insert( make_pair (fNew,
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make_pair(i-1, j+1)));
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cellDetails[i-1][j+1].f = fNew;
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cellDetails[i-1][j+1].g = gNew;
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cellDetails[i-1][j+1].h = hNew;
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cellDetails[i-1][j+1].parent_i = i;
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cellDetails[i-1][j+1].parent_j = j;
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}
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}
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}
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if (isValid (i-1, j-1) == true){
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if (isDestination (i-1, j-1, dest) == true){
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cellDetails[i-1][j-1].parent_i = i;
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cellDetails[i-1][j-1].parent_j = j;
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tracePath (cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i-1][j-1] == false &&
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isUnBlocked(grid, i-1, j-1) == true)
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{
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gNew = cellDetails[i][j].g + 1.414;
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hNew = calculateHValue(i-1, j-1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i-1][j-1].f == FLT_MAX ||
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cellDetails[i-1][j-1].f > fNew)
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{
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openList.insert( make_pair (fNew, make_pair (i-1, j-1)));
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cellDetails[i-1][j-1].f = fNew;
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cellDetails[i-1][j-1].g = gNew;
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cellDetails[i-1][j-1].h = hNew;
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cellDetails[i-1][j-1].parent_i = i;
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cellDetails[i-1][j-1].parent_j = j;
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}
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}
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}
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if (isValid(i+1, j+1) == true){
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if (isDestination(i+1, j+1, dest) == true){
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cellDetails[i+1][j+1].parent_i = i;
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cellDetails[i+1][j+1].parent_j = j;
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tracePath (cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i+1][j+1] == false &&
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isUnBlocked(grid, i+1, j+1) == true)
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{
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gNew = cellDetails[i][j].g + 1.414;
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hNew = calculateHValue(i+1, j+1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i+1][j+1].f == FLT_MAX ||
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cellDetails[i+1][j+1].f > fNew)
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{
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openList.insert(make_pair(fNew,
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make_pair (i+1, j+1)));
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cellDetails[i+1][j+1].f = fNew;
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cellDetails[i+1][j+1].g = gNew;
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cellDetails[i+1][j+1].h = hNew;
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cellDetails[i+1][j+1].parent_i = i;
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cellDetails[i+1][j+1].parent_j = j;
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}
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}
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}
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if (isValid (i+1, j-1) == true)
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{
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if (isDestination(i+1, j-1, dest) == true)
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{
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cellDetails[i+1][j-1].parent_i = i;
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cellDetails[i+1][j-1].parent_j = j;
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tracePath(cellDetails, dest);
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foundDest = true;
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return;
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}
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else if (closedList[i+1][j-1] == false &&
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isUnBlocked(grid, i+1, j-1) == true)
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{
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gNew = cellDetails[i][j].g + 1.414;
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hNew = calculateHValue(i+1, j-1, dest);
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fNew = gNew + hNew;
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if (cellDetails[i+1][j-1].f == FLT_MAX ||
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cellDetails[i+1][j-1].f > fNew)
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{
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openList.insert(make_pair(fNew,
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make_pair(i+1, j-1)));
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cellDetails[i+1][j-1].f = fNew;
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cellDetails[i+1][j-1].g = gNew;
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cellDetails[i+1][j-1].h = hNew;
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cellDetails[i+1][j-1].parent_i = i;
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cellDetails[i+1][j-1].parent_j = j;
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}
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}
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}
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}
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if (foundDest == false)
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printf("Failed to find the Destination Cell\n");
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return;
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}
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int main(){
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int grid[ROW][COL];
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ifstream myfile;
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myfile.open ("input.txt");
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cout<<"\n\tInput Maze\n";
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for(int i = 0; i < ROW; i++)
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for(int j = 0; j < COL; j++)
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myfile >> grid[i][j];
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for(int i = 0; i < ROW; i++){
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cout<<"\t";
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for(int j = 0; j < COL; j++)
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cout << grid[i][j]<<" ";
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cout<<endl;
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}
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Pair src = make_pair(8, 0);
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Pair dest = make_pair(0, 9);
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cout<<"\n\tSource (8, 0) Destination (0, 9)\n";
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aStarSearch(grid, src, dest);
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for(int i = 0; i < ROW; i++){
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cout<<"\t";
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for(int j = 0; j < COL; j++){
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if (arr[i][j]!=0)
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cout << "*"<<" ";
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else
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cout << grid[i][j]<<" ";
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}cout<<endl;
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}
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return(0);
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}

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