Create cpp program for minimum window substring

tanus786#773 please assign me this issue . like to contribute the optimized and efficient code in this repo.

cpp program for minimum window substring

@@ -0,0 +1,27 @@
+string minWindow(string s, string t) {
+        if(s.size() < t.size()){
+            return "";
+        }
+        unordered_map<char,int> map;
+        for(int i=0;i<t.size();i++){
+            map[t[i]]++;
+        }
+        int count=0,start=0,min_length = INT_MAX, min_start = 0;
+        for(int end=0; end<s.size(); end++){
+            if(map[s[end]]>0){
+                count++;
+            }
+            map[s[end]]--; 
+            if(count == t.length()) { 
+                while(start < end && map[s[start]] < 0){
+                    map[s[start]]++, start++;
+                } 
+                if(min_length > end-start){
+                    min_length = end-(min_start=start)+1; 
+                }
+                map[s[start++]]++; 
+                count--;
+            }
+        }
+        return min_length == INT_MAX ? "" : s.substr(min_start, min_length);
+    }