From 708c3eefdf506d2e99df63e44826877980c981cf Mon Sep 17 00:00:00 2001 From: "xin.liu" Date: Thu, 18 Aug 2022 11:08:50 +0800 Subject: [PATCH] =?UTF-8?q?Update=200704.=E4=BA=8C=E5=88=86=E6=B3=95?= =?UTF-8?q?=E6=9F=A5=E6=89=BE=20JavaScript=E5=92=8CTypeScript=E7=89=88?= =?UTF-8?q?=E6=9C=AC?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0704.二分查找.md | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/problems/0704.二分查找.md b/problems/0704.二分查找.md index eec97a78..53f5331a 100644 --- a/problems/0704.二分查找.md +++ b/problems/0704.二分查找.md @@ -290,10 +290,11 @@ func search(nums []int, target int) int { */ var search = function(nums, target) { // right是数组最后一个数的下标,num[right]在查找范围内,是左闭右闭区间 - let left = 0, right = nums.length - 1; + let mid, left = 0, right = nums.length - 1; // 当left=right时,由于nums[right]在查找范围内,所以要包括此情况 while (left <= right) { - let mid = left + Math.floor((right - left)/2); + // 位运算 + 防止大数溢出 + mid = left + ((right - left) >> 1); // 如果中间数大于目标值,要把中间数排除查找范围,所以右边界更新为mid-1;如果右边界更新为mid,那中间数还在下次查找范围内 if (nums[mid] > target) { right = mid - 1; // 去左面闭区间寻找 @@ -316,10 +317,11 @@ var search = function(nums, target) { */ var search = function(nums, target) { // right是数组最后一个数的下标+1,nums[right]不在查找范围内,是左闭右开区间 - let left = 0, right = nums.length; + let mid, left = 0, right = nums.length; // 当left=right时,由于nums[right]不在查找范围,所以不必包括此情况 while (left < right) { - let mid = left + Math.floor((right - left)/2); + // 位运算 + 防止大数溢出 + mid = left + ((right - left) >> 1); // 如果中间值大于目标值,中间值不应在下次查找的范围内,但中间值的前一个值应在; // 由于right本来就不在查找范围内,所以将右边界更新为中间值,如果更新右边界为mid-1则将中间值的前一个值也踢出了下次寻找范围 if (nums[mid] > target) { @@ -340,9 +342,10 @@ var search = function(nums, target) { ```typescript function search(nums: number[], target: number): number { - let left: number = 0, right: number = nums.length - 1; + let mid: number, left: number = 0, right: number = nums.length - 1; while (left <= right) { - let mid: number = left + Math.floor((right - left) / 2); + // 位运算 + 防止大数溢出 + mid = left + ((right - left) >> 1); if (nums[mid] > target) { right = mid - 1; } else if (nums[mid] < target) { @@ -359,9 +362,10 @@ function search(nums: number[], target: number): number { ```typescript function search(nums: number[], target: number): number { - let left: number = 0, right: number = nums.length; + let mid: number, left: number = 0, right: number = nums.length; while (left < right) { - let mid: number = left + Math.floor((right - left) / 2); + // 位运算 + 防止大数溢出 + mid = left +((right - left) >> 1); if (nums[mid] > target) { right = mid; } else if (nums[mid] < target) {