Feature/chapter dynamic programming swift (#608)

* feat: add Swift codes for intro_to_dynamic_programming article * feat: add Swift codes for dp_problem_features article * feat: add Swift codes for dp_solution_pipeline article * feat: add Swift codes for knapsack_problem article * feat: add Swift codes for unbounded_knapsack_problem article * feat: add Swift codes for edit_distance_problem article
2026-08-16 21:50:59 +00:00 · 2023-07-18 12:49:03 +08:00
parent 34985bdf2b
commit 9ea8a73059
13 changed files with 855 additions and 0 deletions
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+/**
+ * File: coin_change_ii.swift
+ * Created Time: 2023-07-16
+ * Author: nuomi1 (nuomi1@qq.com)
+ */
+
+/* 零钱兑换 II：动态规划 */
+func coinChangeIIDP(coins: [Int], amt: Int) -> Int {
+    let n = coins.count
+    // 初始化 dp 表
+    var dp = Array(repeating: Array(repeating: 0, count: amt + 1), count: n + 1)
+    // 初始化首列
+    for i in stride(from: 0, through: n, by: 1) {
+        dp[i][0] = 1
+    }
+    // 状态转移
+    for i in stride(from: 1, through: n, by: 1) {
+        for a in stride(from: 1, through: amt, by: 1) {
+            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 */
+func coinChangeIIDPComp(coins: [Int], amt: Int) -> Int {
+    let n = coins.count
+    // 初始化 dp 表
+    var dp = Array(repeating: 0, count: amt + 1)
+    dp[0] = 1
+    // 状态转移
+    for i in stride(from: 1, through: n, by: 1) {
+        for a in stride(from: 1, through: amt, by: 1) {
+            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]
+}
+
+@main
+enum CoinChangeII {
+    /* Driver Code */
+    static func main() {
+        let coins = [1, 2, 5]
+        let amt = 5
+
+        // 动态规划
+        var res = coinChangeIIDP(coins: coins, amt: amt)
+        print("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: coins, amt: amt)
+        print("凑出目标金额的硬币组合数量为 \(res)")
+    }
+}