mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 22:46:28 +08:00
36 lines
962 B
Swift
36 lines
962 B
Swift
/**
|
||
* File: climbing_stairs_constraint_dp.swift
|
||
* Created Time: 2023-07-15
|
||
* Author: nuomi1 (nuomi1@qq.com)
|
||
*/
|
||
|
||
/* 带约束爬楼梯：动态规划 */
|
||
func climbingStairsConstraintDP(n: Int) -> Int {
|
||
if n == 1 || n == 2 {
|
||
return 1
|
||
}
|
||
// 初始化 dp 表，用于存储子问题的解
|
||
var dp = Array(repeating: Array(repeating: 0, count: 3), count: n + 1)
|
||
// 初始状态：预设最小子问题的解
|
||
dp[1][1] = 1
|
||
dp[1][2] = 0
|
||
dp[2][1] = 0
|
||
dp[2][2] = 1
|
||
// 状态转移：从较小子问题逐步求解较大子问题
|
||
for i in stride(from: 3, through: n, by: 1) {
|
||
dp[i][1] = dp[i - 1][2]
|
||
dp[i][2] = dp[i - 2][1] + dp[i - 2][2]
|
||
}
|
||
return dp[n][1] + dp[n][2]
|
||
}
|
||
|
||
@main
|
||
enum ClimbingStairsConstraintDP {
|
||
/* Driver Code */
|
||
static func main() {
|
||
let n = 9
|
||
|
||
let res = climbingStairsConstraintDP(n: n)
|
||
print("爬 \(n) 阶楼梯共有 \(res) 种方案")
|
||
}
|
||
}
|