mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-25 13:46:30 +08:00
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
/**
|
|
* File: binary_search_recur.kt
|
|
* Created Time: 2024-01-25
|
|
* Author: curtishd (1023632660@qq.com)
|
|
*/
|
|
|
|
package chapter_divide_and_conquer.binary_search_recur
|
|
|
|
/* 二分查找：问题 f(i, j) */
|
|
fun dfs(
|
|
nums: IntArray,
|
|
target: Int,
|
|
i: Int,
|
|
j: Int
|
|
): Int {
|
|
// 若区间为空，代表无目标元素，则返回 -1
|
|
if (i > j) {
|
|
return -1
|
|
}
|
|
// 计算中点索引 m
|
|
val m = (i + j) / 2
|
|
return if (nums[m] < target) {
|
|
// 递归子问题 f(m+1, j)
|
|
dfs(nums, target, m + 1, j)
|
|
} else if (nums[m] > target) {
|
|
// 递归子问题 f(i, m-1)
|
|
dfs(nums, target, i, m - 1)
|
|
} else {
|
|
// 找到目标元素，返回其索引
|
|
m
|
|
}
|
|
}
|
|
|
|
/* 二分查找 */
|
|
fun binarySearch(nums: IntArray, target: Int): Int {
|
|
val n = nums.size
|
|
// 求解问题 f(0, n-1)
|
|
return dfs(nums, target, 0, n - 1)
|
|
}
|
|
|
|
/* Driver Code */
|
|
fun main() {
|
|
val target = 6
|
|
val nums = intArrayOf(1, 3, 6, 8, 12, 15, 23, 26, 31, 35)
|
|
|
|
// 二分查找（双闭区间）
|
|
val index = binarySearch(nums, target)
|
|
println("目标元素 6 的索引 = $index")
|
|
} |