From c9a8b0a9eacc0d9255cacc742d0b8e3a91e98b03 Mon Sep 17 00:00:00 2001 From: hpstory <33348162+hpstory@users.noreply.github.com> Date: Thu, 13 Jul 2023 15:49:40 +0800 Subject: [PATCH] feat(csharp): add csharp code for unbounded knapsack (#596) --- .../coin_change.cs | 71 +++++++++++++++++++ .../coin_change_ii.cs | 68 ++++++++++++++++++ .../unbounded_knapsack.cs | 64 +++++++++++++++++ 3 files changed, 203 insertions(+) create mode 100644 codes/csharp/chapter_dynamic_programming/coin_change.cs create mode 100644 codes/csharp/chapter_dynamic_programming/coin_change_ii.cs create mode 100644 codes/csharp/chapter_dynamic_programming/unbounded_knapsack.cs diff --git a/codes/csharp/chapter_dynamic_programming/coin_change.cs b/codes/csharp/chapter_dynamic_programming/coin_change.cs new file mode 100644 index 000000000..140022bad --- /dev/null +++ b/codes/csharp/chapter_dynamic_programming/coin_change.cs @@ -0,0 +1,71 @@ +/** +* File: coin_change.cs +* Created Time: 2023-07-12 +* Author: hpstory (hpstory1024@163.com) +*/ + +namespace hello_algo.chapter_dynamic_programming; + +public class coin_change { + /* 零钱兑换：动态规划 */ + public int coinChangeDP(int[] coins, int amt) { + int n = coins.Length; + int MAX = amt + 1; + // 初始化 dp 表 + int[,] dp = new int[n + 1, amt + 1]; + // 状态转移：首行首列 + for (int a = 1; a <= amt; a++) { + dp[0, a] = MAX; + } + // 状态转移：其余行列 + for (int i = 1; i <= n; i++) { + for (int a = 1; a <= amt; a++) { + if (coins[i - 1] > a) { + // 若超过背包容量，则不选硬币 i + dp[i, a] = dp[i - 1, a]; + } else { + // 不选和选硬币 i 这两种方案的较小值 + dp[i, a] = Math.Min(dp[i - 1, a], dp[i, a - coins[i - 1]] + 1); + } + } + } + return dp[n, amt] != MAX ? dp[n, amt] : -1; + } + + /* 零钱兑换：状态压缩后的动态规划 */ + public int coinChangeDPComp(int[] coins, int amt) { + int n = coins.Length; + int MAX = amt + 1; + // 初始化 dp 表 + int[] dp = new int[amt + 1]; + Array.Fill(dp, MAX); + dp[0] = 0; + // 状态转移 + for (int i = 1; i <= n; i++) { + for (int a = 1; a <= amt; a++) { + if (coins[i - 1] > a) { + // 若超过背包容量，则不选硬币 i + dp[a] = dp[a]; + } else { + // 不选和选硬币 i 这两种方案的较小值 + dp[a] = Math.Min(dp[a], dp[a - coins[i - 1]] + 1); + } + } + } + return dp[amt] != MAX ? dp[amt] : -1; + } + + [Test] + public void Test() { + int[] coins = { 1, 2, 5 }; + int amt = 4; + + // 动态规划 + int res = coinChangeDP(coins, amt); + Console.WriteLine("凑到目标金额所需的最少硬币数量为 " + res); + + // 状态压缩后的动态规划 + res = coinChangeDPComp(coins, amt); + Console.WriteLine("凑到目标金额所需的最少硬币数量为 " + res); + } +} diff --git a/codes/csharp/chapter_dynamic_programming/coin_change_ii.cs b/codes/csharp/chapter_dynamic_programming/coin_change_ii.cs new file mode 100644 index 000000000..e5acf1a3e --- /dev/null +++ b/codes/csharp/chapter_dynamic_programming/coin_change_ii.cs @@ -0,0 +1,68 @@ +/** +* 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 */ + public 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) { + // 若超过背包容量，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：状态压缩后的动态规划 */ + public 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) { + // 若超过背包容量，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); + + // 状态压缩后的动态规划 + res = coinChangeIIDPComp(coins, amt); + Console.WriteLine("凑出目标金额的硬币组合数量为 " + res); + } +} diff --git a/codes/csharp/chapter_dynamic_programming/unbounded_knapsack.cs b/codes/csharp/chapter_dynamic_programming/unbounded_knapsack.cs new file mode 100644 index 000000000..5213aa26b --- /dev/null +++ b/codes/csharp/chapter_dynamic_programming/unbounded_knapsack.cs @@ -0,0 +1,64 @@ +/** +* File: unbounded_knapsack.cs +* Created Time: 2023-07-12 +* Author: hpstory (hpstory1024@163.com) +*/ + +namespace hello_algo.chapter_dynamic_programming; + +public class unbounded_knapsack { + /* 完全背包：动态规划 */ + public int unboundedKnapsackDP(int[] wgt, int[] val, int cap) { + int n = wgt.Length; + // 初始化 dp 表 + int[,] dp = new int[n + 1, cap + 1]; + // 状态转移 + for (int i = 1; i <= n; i++) { + for (int c = 1; c <= cap; c++) { + if (wgt[i - 1] > c) { + // 若超过背包容量，则不选物品 i + dp[i, c] = dp[i - 1, c]; + } else { + // 不选和选物品 i 这两种方案的较大值 + dp[i, c] = Math.Max(dp[i - 1, c], dp[i, c - wgt[i - 1]] + val[i - 1]); + } + } + } + return dp[n, cap]; + } + + /* 完全背包：状态压缩后的动态规划 */ + public int unboundedKnapsackDPComp(int[] wgt, int[] val, int cap) { + int n = wgt.Length; + // 初始化 dp 表 + int[] dp = new int[cap + 1]; + // 状态转移 + for (int i = 1; i <= n; i++) { + for (int c = 1; c <= cap; c++) { + if (wgt[i - 1] > c) { + // 若超过背包容量，则不选物品 i + dp[c] = dp[c]; + } else { + // 不选和选物品 i 这两种方案的较大值 + dp[c] = Math.Max(dp[c], dp[c - wgt[i - 1]] + val[i - 1]); + } + } + } + return dp[cap]; + } + + [Test] + public void Test() { + int[] wgt = { 1, 2, 3 }; + int[] val = { 5, 11, 15 }; + int cap = 4; + + // 动态规划 + int res = unboundedKnapsackDP(wgt, val, cap); + Console.WriteLine("不超过背包容量的最大物品价值为 " + res); + + // 状态压缩后的动态规划 + res = unboundedKnapsackDPComp(wgt, val, cap); + Console.WriteLine("不超过背包容量的最大物品价值为 " + res); + } +}