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Add code in javascript and typescript. (#690)
* Add binary_search_insertion and binary_search_edge code in javascript and typescript. * code style fix: in FOR loop, use CONST will be nicer. * fix: Code Style * Change ==/!= to ===/!== * Create const by default, change to let if necessary. * Update import files * Update codes/javascript/chapter_searching/binary_search_edge.js Co-authored-by: Justin Tse <xiefahit@gmail.com> * style fix: Delete unnecessary defined type --------- Co-authored-by: Justin Tse <xiefahit@gmail.com>
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codes/javascript/chapter_searching/binary_search_edge.js
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45
codes/javascript/chapter_searching/binary_search_edge.js
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/**
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* File: binary_search_edge.js
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* Created Time: 2023-08-22
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* Author: Gaofer Chou (gaofer-chou@qq.com)
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*/
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const { binarySearchInsertion } = require('./binary_search_insertion.js');
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/* 二分查找最左一个 target */
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function binarySearchLeftEdge(nums, target) {
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// 等价于查找 target 的插入点
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const i = binarySearchInsertion(nums, target);
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// 未找到 target ，返回 -1
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if (i === nums.length || nums[i] !== target) {
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return -1;
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}
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// 找到 target ，返回索引 i
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return i;
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}
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/* 二分查找最右一个 target */
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function binarySearchRightEdge(nums, target) {
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// 转化为查找最左一个 target + 1
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const i = binarySearchInsertion(nums, target + 1);
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// j 指向最右一个 target ，i 指向首个大于 target 的元素
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const j = i - 1;
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// 未找到 target ，返回 -1
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if (j === -1 || nums[j] !== target) {
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return -1;
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}
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// 找到 target ，返回索引 j
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return j;
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}
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/* Driver Code */
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// 包含重复元素的数组
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const nums = [1, 3, 6, 6, 6, 6, 6, 10, 12, 15];
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console.log('\n数组 nums = ' + nums);
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// 二分查找左边界和右边界
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for (const target of [6, 7]) {
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let index = binarySearchLeftEdge(nums, target);
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console.log('最左一个元素 ' + target + ' 的索引为 ' + index);
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index = binarySearchRightEdge(nums, target);
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console.log('最右一个元素 ' + target + ' 的索引为 ' + index);
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}
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/**
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* File: binary_search_insertion.js
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* Created Time: 2023-08-22
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* Author: Gaofer Chou (gaofer-chou@qq.com)
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*/
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/* 二分查找插入点（无重复元素） */
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function binarySearchInsertionSimple(nums, target) {
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let i = 0,
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j = nums.length - 1; // 初始化双闭区间 [0, n-1]
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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, 使用 Math.floor() 向下取整
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if (nums[m] < target) {
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i = m + 1; // target 在区间 [m+1, j] 中
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} else if (nums[m] > target) {
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j = m - 1; // target 在区间 [i, m-1] 中
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} else {
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return m; // 找到 target ，返回插入点 m
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}
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}
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// 未找到 target ，返回插入点 i
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return i;
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}
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/* 二分查找插入点（存在重复元素） */
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function binarySearchInsertion(nums, target) {
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let i = 0,
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j = nums.length - 1; // 初始化双闭区间 [0, n-1]
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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, 使用 Math.floor() 向下取整
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if (nums[m] < target) {
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i = m + 1; // target 在区间 [m+1, j] 中
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} else if (nums[m] > target) {
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j = m - 1; // target 在区间 [i, m-1] 中
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} else {
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j = m - 1; // 首个小于 target 的元素在区间 [i, m-1] 中
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}
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}
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// 返回插入点 i
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return i;
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}
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/* Driver Code */
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// 无重复元素的数组
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let nums = [1, 3, 6, 8, 12, 15, 23, 26, 31, 35];
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console.log('\n数组 nums = ' + nums);
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// 二分查找插入点
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for (const target of [6, 9]) {
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const index = binarySearchInsertionSimple(nums, target);
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console.log('元素 ' + target + ' 的插入点的索引为 ' + index);
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}
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// 包含重复元素的数组
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nums = [1, 3, 6, 6, 6, 6, 6, 10, 12, 15];
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console.log('\n数组 nums = ' + nums);
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// 二分查找插入点
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for (const target of [2, 6, 20]) {
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const index = binarySearchInsertion(nums, target);
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console.log('元素 ' + target + ' 的插入点的索引为 ' + index);
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}
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module.exports = {
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binarySearchInsertion
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};
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47
codes/typescript/chapter_searching/binary_search_edge.ts
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47
codes/typescript/chapter_searching/binary_search_edge.ts
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/**
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* File: binary_search_edge.ts
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* Created Time: 2023-08-22
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* Author: Gaofer Chou (gaofer-chou@qq.com)
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*/
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import { binarySearchInsertion } from './binary_search_insertion';
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/* 二分查找最左一个 target */
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function binarySearchLeftEdge(nums: Array<number>, target: number): number {
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// 等价于查找 target 的插入点
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const i = binarySearchInsertion(nums, target);
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// 未找到 target ，返回 -1
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if (i === nums.length || nums[i] !== target) {
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return -1;
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}
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// 找到 target ，返回索引 i
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return i;
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}
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/* 二分查找最右一个 target */
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function binarySearchRightEdge(nums: Array<number>, target: number): number {
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// 转化为查找最左一个 target + 1
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const i = binarySearchInsertion(nums, target + 1);
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// j 指向最右一个 target ，i 指向首个大于 target 的元素
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const j = i - 1;
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// 未找到 target ，返回 -1
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if (j === -1 || nums[j] !== target) {
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return -1;
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}
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// 找到 target ，返回索引 j
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return j;
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}
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/* Driver Code */
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// 包含重复元素的数组
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let nums= [1, 3, 6, 6, 6, 6, 6, 10, 12, 15];
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console.log('\n数组 nums = ' + nums);
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// 二分查找左边界和右边界
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for (const target of [6, 7]) {
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let index = binarySearchLeftEdge(nums, target);
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console.log('最左一个元素 ' + target + ' 的索引为 ' + index);
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index = binarySearchRightEdge(nums, target);
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console.log('最右一个元素 ' + target + ' 的索引为 ' + index);
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}
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export {};
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/**
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* File: binary_search_insertion.ts
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* Created Time: 2023-08-22
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* Author: Gaofer Chou (gaofer-chou@qq.com)
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*/
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/* 二分查找插入点（无重复元素） */
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function binarySearchInsertionSimple(nums: Array<number>, target: number): number {
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let i = 0,
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j = nums.length - 1; // 初始化双闭区间 [0, n-1]
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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, 使用 Math.floor() 向下取整
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if (nums[m] < target) {
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i = m + 1; // target 在区间 [m+1, j] 中
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} else if (nums[m] > target) {
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j = m - 1; // target 在区间 [i, m-1] 中
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} else {
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return m; // 找到 target ，返回插入点 m
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}
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}
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// 未找到 target ，返回插入点 i
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return i;
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}
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/* 二分查找插入点（存在重复元素） */
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function binarySearchInsertion(nums: Array<number>, target: number): number {
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let i = 0,
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j = nums.length - 1; // 初始化双闭区间 [0, n-1]
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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, 使用 Math.floor() 向下取整
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if (nums[m] < target) {
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i = m + 1; // target 在区间 [m+1, j] 中
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} else if (nums[m] > target) {
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j = m - 1; // target 在区间 [i, m-1] 中
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} else {
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j = m - 1; // 首个小于 target 的元素在区间 [i, m-1] 中
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}
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}
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// 返回插入点 i
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return i;
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}
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/* Driver Code */
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// 无重复元素的数组
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let nums = [1, 3, 6, 8, 12, 15, 23, 26, 31, 35];
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console.log('\n数组 nums = ' + nums);
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// 二分查找插入点
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for (const target of [6, 9]) {
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const index = binarySearchInsertionSimple(nums, target);
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console.log('元素 ' + target + ' 的插入点的索引为 ' + index);
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}
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// 包含重复元素的数组
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nums = [1, 3, 6, 6, 6, 6, 6, 10, 12, 15];
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console.log('\n数组 nums = ' + nums);
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// 二分查找插入点
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for (const target of [2, 6, 20]) {
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const index = binarySearchInsertion(nums, target);
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console.log('元素 ' + target + ' 的插入点的索引为 ' + index);
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}
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export { binarySearchInsertion };
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