Create 139. Word Break.cpp

Author: Yashmenaria1

139. Word Break.cpp

@@ -0,0 +1,22 @@
+class Solution {
+public:
+    unordered_map<string, int> map;
+    int dp[305][305];
+    bool solve(string &s, int n, int start){
+        if(start==n) return true;
+        if(dp[start][n]!=-1) return dp[start][n];
+        for(int i=start; i<n; ++i){
+            string str = s.substr(start,i-start+1);
+            if(map.find(str)!=map.end()){
+                if(solve(s,n,i+1)) return dp[start][n] = true;
+            }
+        }
+        return dp[start][n] = false;
+    }
+    bool wordBreak(string &s, vector<string>& wordDict) {
+        memset(dp,-1,sizeof(dp));
+        for(auto &word : wordDict) map[word]++;
+        int n=s.size();
+        return solve(s,n,0);
+    }
+};