Merge pull request #64 from tanaytoshniwal/master

shortest job first cpu scheduling algorithm and N-Queens Algorithm in C++

Author: probot-auto-merge[bot]

Backtracking/N-Queen/CPP/nqueens.cpp

@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool safe(int* arr[], int row, int col, int size){
+    for(int i=0;i<row;i++){
+        if(arr[i][col] == 1) return false;
+    }
+    for(int i=row, j=col;i>=0 && j>=0;i--, j--){
+        if(arr[i][j] == 1) return false;
+    }
+    for(int i=row, j=col;i>=0 && j<size;i--, j++){
+        if(arr[i][j] == 1) return false;
+    }
+    return true;
+}
+void n_queen(int* arr[], int row, int size){
+    if(row>=size){
+        for(int i=0;i<size;i++){
+            for(int j=0;j<size;j++){
+                cout << arr[i][j] << " ";
+            }
+        }
+        cout << endl;
+        return;
+    }
+    for(int i=0;i<size;i++){
+        if(safe(arr, row, i, size)){
+            arr[row][i] = 1;
+            n_queen(arr, row+1, size);
+            arr[row][i] = 0;
+        }
+    }
+}
+void placeNQueens(int n){
+    int** arr = new int*[n];
+    for(int i=0;i<n;i++){
+        arr[i] = new int[n];
+        for(int j=0;j<n;j++){
+            arr[i][j] = 0;
+        }
+    }
+    n_queen(arr, 0, n);
+}
+int main(){
+  int n; 
+  cin >> n ;
+  placeNQueens(n);
+  return 0;
+}

Operating Systems/Shortest Job First CPU Scheduling Algorithm/CPP/a.out

@@ -0,0 +1,74 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int arr[10][6];
+
+void swap(int *a, int *b){
+    int temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+void arrangeArrival(int num, int arr[][6]){
+    for(int i=0; i<num; i++){
+        for(int j=0; j<num-i-1; j++){
+            if(arr[j][1] > arr[j+1][1])
+                for(int k=0; k<5; k++)
+                    swap(arr[j][k], arr[j+1][k]);
+        }
+    }
+}
+
+void completionTime(int num, int arr[][6]){
+    int temp, val;
+    arr[0][3] = arr[0][1] + arr[0][2];
+    arr[0][5] = arr[0][3] - arr[0][1];
+    arr[0][4] = arr[0][5] - arr[0][2];
+    
+    for(int i=1; i<num; i++){
+        temp = arr[i-1][3];
+        int low = arr[i][2];
+        for(int j=i; j<num; j++){
+            if(temp >= arr[j][1] && low >= arr[j][2]){
+                low = arr[j][2];
+                val = j;
+            }
+        }
+        arr[val][3] = temp + arr[val][2];
+        arr[val][5] = arr[val][3] - arr[val][1];
+        arr[val][4] = arr[val][5] - arr[val][2];
+        for(int k=0; k<6; k++)
+            swap(arr[val][k], arr[i][k]);
+    }
+}
+
+int main(){
+    int num, temp;
+    
+    cout << "Enter number of Process: ";
+    cin >> num;
+    
+    cout << "Enter the process ID: ";
+    for(int i=0; i<num; i++){
+        cout << "Process " << i+1 << endl;
+        cout << "Enter Process Id: ";
+        cin >> arr[i][0];
+        cout << "Enter Arrival Time: ";
+        cin >> arr[i][1];
+        cout << "Enter Burst Time: ";
+        cin >> arr[i][2];
+    }
+    
+    cout << "Before Arrange" << endl;
+    cout << "Process ID\tArrival Time\tBurst Time\n";
+    for(int i=0; i<num; i++)
+        cout << arr[i][0] << "\t\t" << arr[i][1] << "\t\t" << arr[i][2] << "\n";
+    
+    arrangeArrival(num, arr);
+    completionTime(num, arr);
+    cout << "Final Result\n";
+    cout << "Process ID\tArrival Time\tBurst Time\tWaiting Time\tTurnaround Time\n";
+    for(int i=0; i<num; i++)
+        cout << arr[i][0] << "\t\t" << arr[i][1] << "\t\t" << arr[i][2] << "\t\t" << arr[i][4] << "\t\t" << arr[i][5] << "\n";
+    return 0;
+}