feat: 424. Longest Repeating Character Replacement

Author: gwbaik9717

longest-repeating-character-replacement/gwbaik9717.js

@@ -0,0 +1,52 @@
+// Time complexity: O(n)
+// Space complexity: O(1)
+
+/**
+ * @param {string} s
+ * @param {number} k
+ * @return {number}
+ */
+var characterReplacement = function (s, k) {
+  let i = 0;
+  let j = 0;
+
+  const counter = new Map();
+  counter.set(s[i], 1);
+
+  let answer = 1;
+
+  const getMaxCount = () => {
+    let maxCount = 0;
+
+    for (const [key, value] of counter) {
+      maxCount = Math.max(maxCount, value);
+    }
+
+    return maxCount;
+  };
+
+  while (true) {
+    if (s.length - i <= answer) {
+      break;
+    }
+
+    const maxCount = getMaxCount();
+    const totalCount = j - i + 1;
+
+    if (totalCount - maxCount <= k) {
+      j++;
+      counter.set(s[j], (counter.get(s[j]) || 0) + 1);
+      answer = Math.max(totalCount, answer);
+      continue;
+    }
+
+    counter.set(s[i], counter.get(s[i]) - 1);
+    if (counter.get(s[i]) === 0) {
+      counter.delete(s[i]);
+    }
+
+    i++;
+  }
+
+  return answer;
+};