Runtime: 183 ms (Top 88.92%) | Memory: 20.50 MB (Top 92.45%)

Author: AnasImloul

scripts/algorithms/C/Check If a String Contains All Binary Codes of Size K/Check If a String Contains All Binary Codes of Size K.cpp

@@ -1,20 +1,35 @@
+// Runtime: 183 ms (Top 88.92%) | Memory: 20.50 MB (Top 92.45%)
+
 class Solution {
 public:
     bool hasAllCodes(string s, int k) {
-        if (s.size() < k)
+        int n=pow(2,k),m=s.size();
+        vector<bool>check(n,0); //Check Array ,initially all value false;
+        
+        int val=0; //Variable that will help in formation of binary to decimal value of every substring.
+        int i=0,j=0; //Sliding window ponter.
+        
+        while(j<m)
         {
-            return false;
-        }
-        unordered_set<string> binary_codes;
-        for (int i = 0; i < s.size()-k+1; i++)
-        {
-            string str = s.substr(i, k);
-            binary_codes.insert(str);
-            if (binary_codes.size() == (int)pow(2, k))
+            val=val*2+(s[j]-'0'); //Form Binary ,Make it decimal.
+            
+            if(j-i+1<k) //If window size is Less than k ,just j++;
+                j++;
+            else if(j-i+1==k) //If we hit k size.
             {
-                return true;
+                check[val]=true; //Mark check cval true.
+                val=val-(s[i]-'0')*(pow(2,k-1)); //Remove ith value's Calucaltion .
+                i++; //Increment i 
+                j++; //and Increment j to maintain size of window as k
             }
         }
-        return false;
+        
+        for(int l=0;l<n;l++)
+        {
+            if(check[l]==false) //If we didn't find any value ,means that susbtring is missing
+                return false; //Return false;
+        }
+        
+        return true; //Return true;
     }
-};
+};