mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-25 13:16:29 +08:00
2655a2f66a
* Add kotlin code block for chapter_hashing * Add kotlin code block for chapter_heap. * Add kotlin code block for chapter_stack_and_queue and chapter_tree * fix indentation * Update binary_tree.md * style(kotlin): simplify code and improve readability. * simplify kt code for chapter_computational_complexity. * style(kotlin): replace ArrayList with MutableList. * Update subset_sum_i.kt Use kotlin api instead of java. * Update subset_sum_ii.kt use kotlin api instead of java * style(kotlin): replace ArrayList with mutablelist. --------- Co-authored-by: Yudong Jin <krahets@163.com>
55 lines
No EOL
1.6 KiB
Kotlin
55 lines
No EOL
1.6 KiB
Kotlin
/**
|
||
* File: subset_sum_i_native.kt
|
||
* Created Time: 2024-01-25
|
||
* Author: curtishd (1023632660@qq.com)
|
||
*/
|
||
|
||
package chapter_backtracking.subset_sum_i_naive
|
||
|
||
/* 回溯算法：子集和 I */
|
||
fun backtrack(
|
||
state: MutableList<Int>,
|
||
target: Int,
|
||
total: Int,
|
||
choices: IntArray,
|
||
res: MutableList<MutableList<Int>?>
|
||
) {
|
||
// 子集和等于 target 时，记录解
|
||
if (total == target) {
|
||
res.add(state.toMutableList())
|
||
return
|
||
}
|
||
// 遍历所有选择
|
||
for (i in choices.indices) {
|
||
// 剪枝：若子集和超过 target ，则跳过该选择
|
||
if (total + choices[i] > target) {
|
||
continue
|
||
}
|
||
// 尝试：做出选择，更新元素和 total
|
||
state.add(choices[i])
|
||
// 进行下一轮选择
|
||
backtrack(state, target, total + choices[i], choices, res)
|
||
// 回退：撤销选择，恢复到之前的状态
|
||
state.removeAt(state.size - 1)
|
||
}
|
||
}
|
||
|
||
/* 求解子集和 I（包含重复子集） */
|
||
fun subsetSumINaive(nums: IntArray, target: Int): MutableList<MutableList<Int>?> {
|
||
val state = mutableListOf<Int>() // 状态（子集）
|
||
val total = 0 // 子集和
|
||
val res = mutableListOf<MutableList<Int>?>() // 结果列表（子集列表）
|
||
backtrack(state, target, total, nums, res)
|
||
return res
|
||
}
|
||
|
||
/* Driver Code */
|
||
fun main() {
|
||
val nums = intArrayOf(3, 4, 5)
|
||
val target = 9
|
||
val res = subsetSumINaive(nums, target)
|
||
|
||
println("输入数组 nums = ${nums.contentToString()}, target = $target")
|
||
println("所有和等于 $target 的子集 res = $res")
|
||
println("请注意，该方法输出的结果包含重复集合")
|
||
} |