hello-algo/codes/csharp/chapter_dynamic_programming/coin_change_ii.cs
hpstory 56b20eff36
feat(csharp) .NET 8.0 code migration (#966)
* .net 8.0 migration

* update docs

* revert change

* revert change and update appendix docs

* remove static

* Update binary_search_insertion.cs

* Update binary_search_insertion.cs

* Update binary_search_edge.cs

* Update binary_search_insertion.cs

* Update binary_search_edge.cs

---------

Co-authored-by: Yudong Jin <krahets@163.com>
2023-11-26 23:18:44 +08:00

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/**
* File: coin_change_ii.cs
* Created Time: 2023-07-12
* Author: hpstory (hpstory1024@163.com)
*/
namespace hello_algo.chapter_dynamic_programming;
public class coin_change_ii {
/* 零钱兑换 II动态规划 */
int CoinChangeIIDP(int[] coins, int amt) {
int n = coins.Length;
// 初始化 dp 表
int[,] dp = new int[n + 1, amt + 1];
// 初始化首列
for (int i = 0; i <= n; i++) {
dp[i, 0] = 1;
}
// 状态转移
for (int i = 1; i <= n; i++) {
for (int a = 1; a <= amt; a++) {
if (coins[i - 1] > a) {
// 若超过目标金额,则不选硬币 i
dp[i, a] = dp[i - 1, a];
} else {
// 不选和选硬币 i 这两种方案之和
dp[i, a] = dp[i - 1, a] + dp[i, a - coins[i - 1]];
}
}
}
return dp[n, amt];
}
/* 零钱兑换 II空间优化后的动态规划 */
int CoinChangeIIDPComp(int[] coins, int amt) {
int n = coins.Length;
// 初始化 dp 表
int[] dp = new int[amt + 1];
dp[0] = 1;
// 状态转移
for (int i = 1; i <= n; i++) {
for (int a = 1; a <= amt; a++) {
if (coins[i - 1] > a) {
// 若超过目标金额,则不选硬币 i
dp[a] = dp[a];
} else {
// 不选和选硬币 i 这两种方案之和
dp[a] = dp[a] + dp[a - coins[i - 1]];
}
}
}
return dp[amt];
}
[Test]
public void Test() {
int[] coins = [1, 2, 5];
int amt = 5;
// 动态规划
int res = CoinChangeIIDP(coins, amt);
Console.WriteLine("凑出目标金额的硬币组合数量为 " + res);
// 空间优化后的动态规划
res = CoinChangeIIDPComp(coins, amt);
Console.WriteLine("凑出目标金额的硬币组合数量为 " + res);
}
}