sliding window

Author: Simcoderan

424.Longest Repeating Character Replacement/Solution.java

@@ -0,0 +1,37 @@
+class Solution {
+    public int characterReplacement(String s, int k) {
+
+        int [] freq = new int[26];
+        int left=0;
+        int maxFreq=0;
+        int maxWindow=0;
+
+        for (int right=0;right<s.length();right++){
+            //update the frequency of the current characters
+            freq[s.charAt(right)-'A']++;
+            //update thr max frequency
+            maxFreq=Math.max(maxFreq,freq[s.charAt(right)-'A']);
+
+            int windowLength=right-left+1;
+            //if the windowLength-max frequency>k
+            //then we need to shrink the window
+
+            if(windowLength-maxFreq>k){
+                freq[s.charAt(left)-'A']--;
+                left++;
+
+            }
+
+            windowLength=right-left+1;
+            maxWindow=Math.max(maxWindow,windowLength);
+
+
+
+        }
+
+        return maxWindow;
+        
+
+        
+    }
+}