add: 最长重复子数组

README.md

@@ -376,6 +376,11 @@ LeetCode 与 LintCode 解题记录。此为个人练习仓库，代码中对重
   - LeetCode 739. 每日温度 <https://leetcode-cn.com/problems/daily-temperatures/>
   - LintCode 1060. 每日温度 <https://www.lintcode.com/problem/daily-temperatures/description>
 
+- [最长重复子数组](src/array/maximum-length-of-repeated-subarray.js)
+
+  - LeetCode 718. 最长重复子数组 <https://leetcode-cn.com/problems/maximum-length-of-repeated-subarray/>
+  - LintCode 79. 最长公共子串 <https://www.lintcode.com/problem/longest-common-substring/description>
+
 ## 栈
 
 - [最大矩阵](src/stack/maximal-rectangle.js)

src/array/maximum-length-of-repeated-subarray.js

@@ -0,0 +1,38 @@
+// 输入:
+// A: [1, 2, 3, 2, 1]
+// B: [3, 2, 1, 4, 7]
+
+const maxLength = function (A, B, addA, addB, len) {
+  addA = (addA > 0) ? addA : 0
+  addB = (addB > 0) ? addB : 0
+  let result = 0
+  let k = 0
+  for (let i = 0; i < len && (k + len - i > result); i++) {
+    if (A[i + addA] === B[i + addB]) {
+      k++
+    } else {
+      k = 0
+    }
+    result = Math.max(result, k)
+  }
+  return result
+}
+
+/**
+ * @param {number[]} A
+ * @param {number[]} B
+ * @return {number}
+ */
+export const findLength = function (A, B) {
+  const ALen = A.length
+  const BLen = B.length
+  let result = 0
+  for (let i = 1; i < ALen + BLen; i++) {
+    if (result >= (ALen + BLen - i)) {
+      return result
+    }
+    const len = Math.min(i, ALen, BLen, (ALen + BLen - i))
+    result = Math.max(maxLength(A, B, ALen - i, i - ALen, len), result)
+  }
+  return result
+}

test/array/maximum-length-of-repeated-subarray.test.js

@@ -0,0 +1,5 @@
+import { findLength } from '../../src/array/maximum-length-of-repeated-subarray.js'
+
+test('最长重复子数组', () => {
+  expect(findLength([1, 2, 3, 2, 1], [3, 2, 1, 4, 7])).toBe(3)
+})