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https://github.com/krahets/hello-algo.git
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7cdfa03e68
* feat(kotlin):new kotlin support files
* fix(kotlin):
reviewed the formatting, comments and so on.
* fix(kotlin): fix the indentation and format
* feat(kotlin): Add kotlin code for the backtraking chapter.
* fix(kotlin): fix incorrect output of preorder_traversal_iii_template.kt file
* fix(kotlin): simplify kotlin codes
* fix(kotlin): modify n_queens.kt for consistency.
* feat(kotlin): add kotlin code for computational complexity.
* fix(kotlin): remove iteration folder.
* fix(kotlin): remove n_queens.kt file out of folder.
* fix(kotlin): remove some folders.
* style(kotlin): modified two chapters.
* feat(kotlin): add kotlin code for divide and conquer.
* Update build_tree.kt
* Update hanota.kt
* Delete codes/kotlin/chapter_backtracking directory
* Delete codes/kotlin/chapter_computational_complexity directory
* Delete codes/kotlin/chapter_divide_and_conquer directory
* feat(kotlin): add kotlin code for divide and conquer.
* Update hanota.kt
49 lines
No EOL
1.1 KiB
Kotlin
49 lines
No EOL
1.1 KiB
Kotlin
/**
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* File: binary_search_recur.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_divide_and_conquer.binary_search_recur
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/* 二分查找：问题 f(i, j) */
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fun dfs(
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nums: IntArray,
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target: Int,
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i: Int,
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j: Int
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): Int {
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// 若区间为空，代表无目标元素，则返回 -1
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if (i > j) {
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return -1
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}
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// 计算中点索引 m
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val m = (i + j) / 2
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return if (nums[m] < target) {
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// 递归子问题 f(m+1, j)
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dfs(nums, target, m + 1, j)
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} else if (nums[m] > target) {
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// 递归子问题 f(i, m-1)
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dfs(nums, target, i, m - 1)
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} else {
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// 找到目标元素，返回其索引
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m
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}
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}
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/* 二分查找 */
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fun binarySearch(nums: IntArray, target: Int): Int {
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val n = nums.size
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// 求解问题 f(0, n-1)
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return dfs(nums, target, 0, n - 1)
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}
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/* Driver Code */
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fun main() {
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val target = 6
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val nums = intArrayOf(1, 3, 6, 8, 12, 15, 23, 26, 31, 35)
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// 二分查找（双闭区间）
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val index = binarySearch(nums, target)
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println("目标元素 6 的索引 = $index")
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} |