mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 04:06:29 +08:00
42f48405ef
* feat(kotlin): add kotlin code for utils file. * Update ListNode.kt * Update PrintUtil.kt * fix: add the header comment for linkedlist_stack class. * fix(kotlin): fix the kotlin file name. * delete blank line in main function * add comment for class head. * delete the old file. * fix the created time * delete blank line beneath files. --------- Co-authored-by: Yudong Jin <krahets@163.com>
38 lines
No EOL
907 B
Kotlin
38 lines
No EOL
907 B
Kotlin
/**
|
|
* File: climbing_stairs_dfs_mem.kt
|
|
* Created Time: 2024-01-25
|
|
* Author: curtishd (1023632660@qq.com)
|
|
*/
|
|
|
|
package chapter_dynamic_programming
|
|
|
|
import java.util.*
|
|
|
|
/* 记忆化搜索 */
|
|
fun dfs(i: Int, mem: IntArray): Int {
|
|
// 已知 dp[1] 和 dp[2] ,返回之
|
|
if (i == 1 || i == 2) return i
|
|
// 若存在记录 dp[i] ,则直接返回之
|
|
if (mem[i] != -1) return mem[i]
|
|
// dp[i] = dp[i-1] + dp[i-2]
|
|
val count = dfs(i - 1, mem) + dfs(i - 2, mem)
|
|
// 记录 dp[i]
|
|
mem[i] = count
|
|
return count
|
|
}
|
|
|
|
/* 爬楼梯:记忆化搜索 */
|
|
fun climbingStairsDFSMem(n: Int): Int {
|
|
// mem[i] 记录爬到第 i 阶的方案总数,-1 代表无记录
|
|
val mem = IntArray(n + 1)
|
|
Arrays.fill(mem, -1)
|
|
return dfs(n, mem)
|
|
}
|
|
|
|
/* Driver Code */
|
|
fun main() {
|
|
val n = 9
|
|
|
|
val res: Int = climbingStairsDFSMem(n)
|
|
println("爬 $n 阶楼梯共有 $res 种方案")
|
|
} |