Create WordSearchll .cpp

Author: shreyashgupta

22- Trie Data Structure/WordSearchll .cpp

@@ -0,0 +1,190 @@
+//Given a 2D board and a list of words from the dictionary, find all words in the board.
+//Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" 
+//cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once in a word.
+
+
+
+
+#include <bits/stdc++.h> 
+using namespace std; 
+  
+const int ALPHABET_SIZE = 26; 
+  
+// trie node 
+
+class Solution {
+public:
+    vector<string>ret;
+    struct TrieNode 
+    { 
+        struct TrieNode *children[ALPHABET_SIZE]; 
+        bool isEndOfWord; 
+    }; 
+
+    struct TrieNode *getNode(void) 
+    { 
+        struct TrieNode *pNode =  new TrieNode; 
+
+        pNode->isEndOfWord = false; 
+
+        for (int i = 0; i < ALPHABET_SIZE; i++) 
+            pNode->children[i] = NULL; 
+
+        return pNode; 
+    } 
+    void insert(struct TrieNode *root, string key) 
+    { 
+        struct TrieNode *pCrawl = root; 
+
+        for (int i = 0; i < key.length(); i++) 
+        { 
+            int index = key[i] - 'a'; 
+            if (!pCrawl->children[index]) 
+                pCrawl->children[index] = getNode(); 
+
+            pCrawl = pCrawl->children[index]; 
+        } 
+        pCrawl->isEndOfWord = true; 
+    } 
+    int search(struct TrieNode *root, string key) 
+    { 
+        struct TrieNode *pCrawl = root; 
+
+        for (int i = 0; i < key.length(); i++) 
+        { 
+            int index = key[i] - 'a'; 
+            if (!pCrawl->children[index]) 
+                return 0; 
+
+            pCrawl = pCrawl->children[index]; 
+        } 
+        if(pCrawl->isEndOfWord==false && pCrawl!=NULL)
+            return 1;
+        if(pCrawl != NULL && pCrawl->isEndOfWord)
+            return 2;
+        return -1;
+    } 
+    void fn(struct TrieNode*root,vector<vector<char>>& board,string str,int i,int j)
+    {
+            char store =board[i][j];
+            board[i][j]='0';
+            int temp=0;
+            if(i-1 >=0 && board[i-1][j]!='0')
+            {   
+                
+                str.push_back(board[i-1][j]);
+                backtrack(root,board,str,i-1,j);
+                str.pop_back();
+                board[i][j]=store;
+            }
+            if(j-1 >=0 && board[i][j-1]!='0')
+            {
+                str.push_back(board[i][j-1]);
+                backtrack(root,board,str,i,j-1);
+                str.pop_back();
+                board[i][j]=store;
+            }
+            if(i+1 < board.size()  && board[i+1][j]!='0')
+            {
+                str.push_back(board[i+1][j]);
+                backtrack(root,board,str,i+1,j);
+                str.pop_back();
+                board[i][j]=store;
+
+            }
+            if(j+1 <board[0].size() && board[i][j+1]!='0')
+            {
+                str.push_back(board[i][j+1]);
+                backtrack(root,board,str,i,j+1);
+                str.pop_back();
+                board[i][j]=store;
+                    
+            }
+            board[i][j]=store;
+    }
+    int backtrack(struct TrieNode*root,vector<vector<char>>& board,string str,int i,int j)
+    {
+        if(search(root,str)==0)
+        {
+            return 0;
+        }
+        else
+        {
+            if(search(root,str)==2)
+                {
+                    ret.push_back(str);
+                }
+            char store =board[i][j];
+            board[i][j]='0';
+            int temp=0;
+            if(i-1 >=0 && board[i-1][j]!='0')
+            {   
+                 board[i][j]='0';
+                str.push_back(board[i-1][j]);
+                temp=backtrack(root,board,str,i-1,j);
+                str.pop_back();
+                    board[i][j]=store;
+            }
+            if(j-1 >=0 && board[i][j-1]!='0')
+            {
+                 board[i][j]='0';
+                str.push_back(board[i][j-1]);
+                temp=backtrack(root,board,str,i,j-1);
+                str.pop_back();
+                     board[i][j]=store;
+            }
+            if(i+1 < board.size()  && board[i+1][j]!='0')
+            {
+                 board[i][j]='0';
+                str.push_back(board[i+1][j]);
+                temp=backtrack(root,board,str,i+1,j);
+                str.pop_back();
+                    board[i][j]=store;
+            }
+            if(j+1 <board[0].size() && board[i][j+1]!='0')
+            {
+                 board[i][j]='0';
+                str.push_back(board[i][j+1]);
+                temp=backtrack(root,board,str,i,j+1);
+                str.pop_back();
+                board[i][j]=store;
+                    
+            }
+            board[i][j]=store;
+            return temp;
+            
+        }
+    }
+    vector<string> findWords(vector<vector<char>>& board, vector<string>& words) {
+    int n = words.size(); 
+    if(words.size()==0)
+    {
+        vector<string>r;
+        return r;
+    }
+    struct TrieNode *root = getNode(); 
+    vector<vector<char>>copy=board;
+    // Construct trie 
+    for (int i = 0; i < n; i++) 
+        insert(root, words[i]);    
+    for(int i=0;i<board.size();i++)
+        for(int j=0;j<board[0].size();j++)
+        {
+            copy=board;
+            string str(1,board[i][j]);   
+            backtrack(root,copy,str,i,j);
+           
+        }
+    vector<string>::iterator ip; 
+  if(ret.size()==0)
+      return ret;
+    sort(ret.begin(),ret.end());
+        vector<string>final;
+    for (int i=1;i<ret.size();i++) { 
+        if(ret[i-1]!=ret[i])
+            final.push_back(ret[i-1]);
+    }
+        final.push_back(ret[ret.size()-1]);
+        return final;
+    }
+};