문제 추가

Author: jdalma

longest-repeating-character-replacement/jdalma.kt

@@ -0,0 +1,62 @@
+package leetcode_study
+
+import io.kotest.matchers.shouldBe
+import org.junit.jupiter.api.Test
+import kotlin.math.max
+
+class `longest-repeating-character-replacement` {
+
+    fun characterReplacement(s: String, k: Int): Int {
+        return usingSlidingWindow(s, k)
+    }
+
+    /**
+     * TC: O(n^3), SC: O(1) 시간초과 !!!
+     */
+    private fun usingBruteForce(s: String, k: Int): Int {
+        var result = 0
+
+        for (start in s.indices) {
+            for (end in start until s.length) {
+                val counter = mutableMapOf<Char, Int>()
+                for (i in start .. end) {
+                    counter[s[i]] = counter.getOrDefault(s[i], 0) + 1
+                }
+
+                val maxCount = counter.values.maxOrNull() ?: 0
+                if ((end - start + 1) - maxCount <= k) {
+                    result = max(result, end - start + 1)
+                }
+            }
+        }
+
+        return result
+    }
+
+    /**
+     * TC: O(n), SC: O(1)
+     */
+    private fun usingSlidingWindow(s: String, k: Int): Int {
+        var (maxLength, start) = 0 to 0
+        val count = IntArray(26)
+
+        for (end in s.indices) {
+            count[s[end] - 'A']++
+            while (end - start + 1 - count.max() > k) {
+                count[s[start] - 'A']--
+                start++
+            }
+            maxLength = max(end - start + 1, maxLength)
+        }
+
+        return maxLength
+    }
+
+    @Test
+    fun `문자열이 주어졌을 때 동일한 문자를 포함하는 가장 긴 부분 문자열의 길이를 반환한다 문자는 최대 k번 변경할 수 있다`() {
+        characterReplacement("ABAB", 2) shouldBe 4
+        characterReplacement("AABAB", 2) shouldBe 5
+        characterReplacement("AABAB", 1) shouldBe 4
+        characterReplacement("AABBAB", 1) shouldBe 4
+    }
+}