diff --git a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md index 260462c2..a81b3641 100644 --- a/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md +++ b/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md @@ -480,6 +480,62 @@ var searchRange = function(nums, target) { return [-1, -1]; }; ``` + + +### TypeScript + +```typescript +function searchRange(nums: number[], target: number): number[] { + const leftBoard: number = getLeftBorder(nums, target); + const rightBoard: number = getRightBorder(nums, target); + // target 在nums区间左侧或右侧 + if (leftBoard === (nums.length - 1) || rightBoard === 0) return [-1, -1]; + // target 不存在与nums范围内 + if (rightBoard - leftBoard <= 1) return [-1, -1]; + // target 存在于nums范围内 + return [leftBoard + 1, rightBoard - 1]; +}; +// 查找第一个大于target的元素下标 +function getRightBorder(nums: number[], target: number): number { + let left: number = 0, + right: number = nums.length - 1; + // 0表示target在nums区间的左边 + let rightBoard: number = 0; + while (left <= right) { + let mid = Math.floor((left + right) / 2); + if (nums[mid] <= target) { + // 右边界一定在mid右边(不含mid) + left = mid + 1; + rightBoard = left; + } else { + // 右边界在mid左边(含mid) + right = mid - 1; + } + } + return rightBoard; +} +// 查找第一个小于target的元素下标 +function getLeftBorder(nums: number[], target: number): number { + let left: number = 0, + right: number = nums.length - 1; + // length-1表示target在nums区间的右边 + let leftBoard: number = nums.length - 1; + while (left <= right) { + let mid = Math.floor((left + right) / 2); + if (nums[mid] >= target) { + // 左边界一定在mid左边(不含mid) + right = mid - 1; + leftBoard = right; + } else { + // 左边界在mid右边(含mid) + left = mid + 1; + } + } + return leftBoard; +} +``` + + ### Scala ```scala object Solution { @@ -527,5 +583,6 @@ object Solution { } ``` + -----------------------