parent
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commit
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# EditorConfig is awesome: https://EditorConfig.org
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# Unix-style newlines with a newline ending every file
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[*]
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end_of_line = lf
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insert_final_newline = true
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# Matches multiple files with brace expansion notation
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# Set default charset
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[*.{ts,js,py,java,go,c,cpp,cs}]
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charset = utf-8
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# 4 space indentation
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[*.{ts,js,py,java,go,c,cpp,cs}]
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indent_style = space
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indent_size = 4
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/*
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* File: binary_search.ts
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* Created Time: 2022-12-27
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* Author: Daniel (better.sunjian@gmail.com)
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*/
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/* 二分查找(双闭区间) */
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const binarySearch = function (nums: number[], target: number): number {
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// 初始化双闭区间 [0, n-1] ,即 i, j 分别指向数组首元素、尾元素
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let i = 0, j = nums.length - 1;
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// 循环,当搜索区间为空时跳出(当 i > j 时为空)
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while (i <= j) {
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let m = Math.floor(i + (j - i) / 2); // 计算中点索引 m
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if (nums[m] < target) { // 此情况说明 target 在区间 [m+1, j] 中
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i = m + 1;
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} else if (nums[m] > target) { // 此情况说明 target 在区间 [i, m-1] 中
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j = m - 1;
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} else { // 找到目标元素,返回其索引
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return m;
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}
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}
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return -1; // 未找到目标元素,返回 -1
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}
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/* 二分查找(左闭右开) */
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const binarySearch1 = function (nums: number[], target: number): number {
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// 初始化左闭右开 [0, n) ,即 i, j 分别指向数组首元素、尾元素+1
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let i = 0, j = nums.length;
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// 循环,当搜索区间为空时跳出(当 i = j 时为空)
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while (i < j) {
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const m = Math.floor(i + (j - i) / 2); // 计算中点索引 m
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if (nums[m] < target) { // 此情况说明 target 在区间 [m+1, j) 中
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i = m + 1;
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} else if (nums[m] > target) { // 此情况说明 target 在区间 [i, m) 中
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j = m;
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} else { // 找到目标元素,返回其索引
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return m;
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}
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}
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return -1; // 未找到目标元素,返回 -1
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}
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/* Driver Code */
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const target = 6;
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const nums = [ 1, 3, 6, 8, 12, 15, 23, 67, 70, 92 ];
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/* 二分查找(双闭区间) */
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let index = binarySearch(nums, target);
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console.info('目标元素 6 的索引 = %d', index);
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/* 二分查找(左闭右开) */
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index = binarySearch1(nums, target);
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console.info('目标元素 6 的索引 = %d', index);
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