Create Day 18 Permutation in String.cpp

Author: tusharjaiswal123

Day 18 Permutation in String.cpp

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+PROBLEM:
+
+
+Given two strings s1 and s2, write a function to return true if s2 contains the permutation of s1. In other words, one of the
+first string's permutations is the substring of the second string.
+
+ 
+Example 1:
+Input: s1 = "ab" s2 = "eidbaooo"
+Output: True
+Explanation: s2 contains one permutation of s1 ("ba").
+
+Example 2:
+Input:s1= "ab" s2 = "eidboaoo"
+Output: False
+ 
+Note:
+
+1.The input strings only contain lower case letters.
+2.The length of both given strings is in range [1, 10,000].
+
+
+
+SOLUTION:
+
+
+
+class Solution {
+public:
+    bool checkInclusion(string s1, string s2) {
+        
+        vector<int> a(26,0);     //Sliding Window
+        vector<int> b(26,0);
+        
+        int i,n1,n2;
+        n1=s1.length();
+        n2=s2.length();
+        
+        if(n1>n2)
+            return false;
+        
+        for(i=0;i<n1;i++)
+        {
+            a[s1[i]-'a']++;
+            b[s2[i]-'a']++;
+        }
+        
+        if(a==b)
+            return true;
+        
+        int p;
+        p=0;
+        for(i=n1;i<n2;i++)
+        {
+            b[s2[p]-'a']--;
+            b[s2[i]-'a']++;
+            p++;
+            
+            if(a==b)
+                return true;
+        }
+        
+        return false;
+        
+    }
+};