add: 山脉数组中查找目标值

test/array/find-in-mountain-array.test.js

@@ -0,0 +1,30 @@
+import { peakIndexInMountainArray, mountainSequence, findInMountainArray } from '../../src/array/find-in-mountain-array'
+
+test('山脉数组的峰顶索引', () => {
+  expect(peakIndexInMountainArray([0, 1, 0])).toBe(1)
+  expect(peakIndexInMountainArray([0, 2, 1, 0])).toBe(1)
+})
+
+test('山脉序列中的最大值', () => {
+  expect(mountainSequence([1, 2, 4, 8, 6, 3])).toBe(8)
+  expect(mountainSequence([10, 9, 8, 7])).toBe(10)
+})
+
+function MountainArray (arr) {
+  this.arr = arr
+  // @param {number} index
+  // @return {number}
+  this.get = function (index) {
+    return this.arr[index]
+  }
+
+  // @return {number}
+  this.length = function () {
+    return this.arr.length
+  }
+};
+
+test('山脉数组中查找目标值', () => {
+  expect(findInMountainArray(3, new MountainArray([1, 2, 3, 4, 5, 3, 1]))).toBe(2)
+  expect(findInMountainArray(3, new MountainArray([0, 1, 2, 4, 2, 1]))).toBe(-1)
+})