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0140-word-break-ii/0140-word-break-ii.cpp

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+class Solution {
+public:
+    vector<string> wordBreak(string s, vector<string>& wordDict) {
+        //insert all the words in the set
+        unordered_set<string> set;
+        vector<string> res;
+        for(auto word:wordDict)
+            set.insert(word);
+        //to store the current string 
+        string curr="";
+        findHelper(0,s,curr,set,res);
+        return res;
+    }
+
+    void findHelper(int ind,string s,string curr,unordered_set<string> set,vector<string>& res)
+    {
+        if(ind==s.length())
+        {
+            //we have reached end
+            curr.pop_back(); //remove the trailing space
+            res.push_back(curr);
+        }
+        string str="";
+        for(int i=ind;i<s.length();i++)
+        {
+            //get every substring and check if it exists in set
+            str.push_back(s[i]);
+            if(set.count(str))
+            {
+                //we have got a word in dict 
+                //explore more and get other substrings
+                findHelper(i+1,s,curr+str+" ",set,res);
+            }
+        }
+    }
+};