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Add the section of binary search insertion. (#671)

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Refactor the section of binary search edge.
Finetune the figures of binary search.
This commit is contained in:
Yudong Jin
2023-08-04 05:16:56 +08:00
committed by GitHub
parent 3d81b2d954
commit 71074d88f6
52 changed files with 546 additions and 621 deletions
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57
codes/javascript/chapter_searching/binary_search_edge.js
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@ -1,57 +0,0 @@
/**
* File: binary_search_edge.js
* Created Time: 2023-06-04
* Author: Justin (xiefahit@gmail.com)
*/
/* 二分查找最左一个元素 */
function binarySearchLeftEdge(nums, target) {
let i = 0,
j = nums.length - 1; // 初始化双闭区间 [0, n-1]
while (i <= j) {
let m = Math.floor((i + j) / 2); // 计算中点索引 m
if (nums[m] < target) {
i = m + 1; // target 在区间 [m+1, j] 中
} else if (nums[m] > target) {
j = m - 1; // target 在区间 [i, m-1] 中
} else {
j = m - 1; // 首个小于 target 的元素在区间 [i, m-1] 中
}
}
if (i === nums.length || nums[i] != target) {
return -1; // 未找到目标元素，返回 -1
}
return i;
}
/* 二分查找最右一个元素 */
function binarySearchRightEdge(nums, target) {
let i = 0,
j = nums.length - 1; // 初始化双闭区间 [0, n-1]
while (i <= j) {
let m = Math.floor((i + j) / 2); // 计算中点索引 m
if (nums[m] < target) {
i = m + 1; // target 在区间 [m+1, j] 中
} else if (nums[m] > target) {
j = m - 1; // target 在区间 [i, m-1] 中
} else {
i = m + 1; // 首个大于 target 的元素在区间 [m+1, j] 中
}
}
if (j < 0 || nums[j] != target) {
return -1; // 未找到目标元素，返回 -1
}
return j;
}
/* Driver Code */
let target = 6;
const nums = [1, 3, 6, 6, 6, 6, 6, 10, 12, 15];
// 二分查找最左一个元素
let index_left = binarySearchLeftEdge(nums, target);
console.log('数组中最左一个元素 6 的索引 = ', index_left);
// 二分查找最右一个元素
let index_right = binarySearchRightEdge(nums, target);
console.log('数组中最右一个元素 6 的索引 = ', index_right);