add code for Permutation in String (567.cpp)

Author: PriyanshVerma

leetcode/cpp/string/567.cpp

@@ -0,0 +1,32 @@
+class Solution {
+public:
+    bool checkInclusion(string sml, string lrg) {
+        if (lrg.length() < sml.length())
+            return false;
+        
+        unordered_map<char, int> targetMap, haveMap;
+        for(char c: sml) {
+            targetMap[c]++;
+        }
+        
+        for(char c: lrg.substr(0, sml.length())) {
+            haveMap[c]++;
+        }
+        
+        int st=0, en=sml.length()-1;
+        while(en < lrg.length()) {
+            if (targetMap == haveMap) {
+                return true;
+            }
+            
+            haveMap[lrg[st]]--; 
+            if (haveMap[lrg[st]]==0) haveMap.erase(lrg[st]);
+            st++;
+            en++; 
+            if (en<lrg.length())
+                haveMap[lrg[en]]++;
+        }
+        return false;
+        
+    } 
+};