TRIE DS

Author: gs146

Word Search II

@@ -0,0 +1,87 @@
+class Solution {
+    struct node
+    {
+        char c;
+        int ends; //can be bool to in this qurstion
+        string word;
+        node* child[26];
+    };
+    
+    struct  node* getNode(char c)
+    {
+        node *newnode = new node;
+        newnode->c = c;
+        newnode->ends = 0;
+        newnode->word = "";
+        for(int i=0;i<26;i++)
+            newnode->child[i] =NULL;
+        return newnode;
+    }
+    
+    node * root = getNode('/');
+    
+    void insert(string s)
+    {
+        node *curr=root;
+        int index,i=0;
+        while(s[i])
+        {
+            index = s[i]-'a';
+            if(curr->child[index]==NULL)
+                curr->child[index] = getNode(s[i]);
+            curr = curr->child[index];
+            i=i+1;
+        }
+        curr->ends=1;
+        curr->word = s;
+    }
+    
+    void solve(vector<vector<char>>& board, int i, int j, int r, int c, vector<string> &ans, node*curr)
+    {
+        int  idx = board[i][j]-'a';
+        
+        if(board[i][j] == '$' || curr->child[idx]==NULL)
+            return;
+        
+        curr = curr->child[idx];
+        
+        if(curr->ends > 0)
+        {
+            ans.push_back(curr->word);
+            curr->ends -= 1;
+        }
+        
+        char ch = board[i][j];
+        
+        board[i][j] = '$';
+        if(i>0)
+        solve(board, i-1, j, r,c, ans, curr);
+        
+        if(i<r-1)
+            solve(board, i+1, j, r,c, ans, curr);
+        if(j>0)
+            solve(board, i, j-1, r,c, ans, curr);
+        if(j<c-1)
+            solve(board, i, j+1, r,c, ans, curr);
+        board[i][j] = ch;
+    }
+    
+public:
+    vector<string> findWords(vector<vector<char>>& board, vector<string>& words) 
+    {
+     
+        int r = board.size();
+        int c = board[0].size();
+        
+        for(int i=0;i<words.size();i++)
+            insert(words[i]);
+        
+        vector<string> ans;
+        for(int i=0;i<r;i++)
+        {
+            for(int j=0;j<c;j++)
+                solve(board, i, j, r, c, ans, root);
+        }
+        return ans;
+    }
+};