From 8b4d3300c3573c0276be2453d77b9674ba51745e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E4=BD=9C=E5=8B=8B?= <59754483+Zuoxun@users.noreply.github.com> Date: Sat, 7 Oct 2023 21:40:17 +0800 Subject: [PATCH] Add Coin change in C code (#833) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * Update vector.h 增加功能列表： 获取向量的第 i 个元素 设置向量的第 i 个元素 向量扩容 向量缩容 向量插入元素 向量删除元素 向量交换元素 向量是否为空 向量是否已满 向量是否相等 对向量内部进行排序（升序/降序） 对向量某段数据排序（升序/降序） * Create hanota.c * 新增binary_search_recur.c * Update vector.h * Delete codes/c/chapter_divide_and_conquer directory * Update vector.h * Create binary_search_recur.c * Delete codes/chapter_divide_and_conquer directory * Update vector.h * old vector.h * Create coin_change.c * Update coin_change.c * Update coin_change.c * Create CMakeLists.txt * Update coin_change.c --------- Co-authored-by: Yudong Jin --- .../CMakeLists.txt | 1 + .../chapter_dynamic_programming/coin_change.c | 78 +++++++++++++++++++ 2 files changed, 79 insertions(+) create mode 100644 codes/c/chapter_dynamic_programming/coin_change.c diff --git a/codes/c/chapter_dynamic_programming/CMakeLists.txt b/codes/c/chapter_dynamic_programming/CMakeLists.txt index 292b26f3..d415d188 100644 --- a/codes/c/chapter_dynamic_programming/CMakeLists.txt +++ b/codes/c/chapter_dynamic_programming/CMakeLists.txt @@ -2,3 +2,4 @@ add_executable(min_cost_climbing_stairs_dp min_cost_climbing_stairs_dp.c) add_executable(min_path_sum min_path_sum.c) add_executable(knapsack knapsack.c) add_executable(unbounded_knapsack unbounded_knapsack.c) +add_executable(coin_change coin_change.c) diff --git a/codes/c/chapter_dynamic_programming/coin_change.c b/codes/c/chapter_dynamic_programming/coin_change.c new file mode 100644 index 00000000..59a1df32 --- /dev/null +++ b/codes/c/chapter_dynamic_programming/coin_change.c @@ -0,0 +1,78 @@ +/** + * File: coin_change.c + * Created Time: 2023-10-02 + * Author: Zuoxun (845242523@qq.com) + */ + +#include "../utils/common.h" + +/* 求最小值 */ +int min(int a, int b) { + return a < b ? a : b; +} + +/* 零钱兑换：动态规划 */ +int coinChangeDP(int coins[], int amt, int coinsSize) { + int n = coinsSize; + int MAX = amt + 1; + // 初始化 dp 表 + int dp[n + 1][amt + 1]; + memset(dp, 0, sizeof(dp)); + // 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] = 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：空间优化后的动态规划 */ +int coinChangeDPComp(int coins[], int amt, int coinsSize) { + int n = coinsSize; + int MAX = amt + 1; + // 初始化 dp 表 + int dp[amt + 1]; + memset(dp, MAX, sizeof(dp)); + 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] = min(dp[a], dp[a - coins[i - 1]] + 1); + } + } + } + return dp[amt] != MAX ? dp[amt] : -1; +} + +/* Driver code */ +int main() { + int coins[] = {1, 2, 5}; + int coinsSize = sizeof(coins) / sizeof(coins[0]); + int amt = 4; + + // 动态规划 + int res = coinChangeDP(coins, amt, coinsSize); + printf("凑到目标金额所需的最少硬币数量为 %d\n", res); + + // 空间优化后的动态规划 + res = coinChangeDPComp(coins, amt, coinsSize); + printf("凑到目标金额所需的最少硬币数量为 %d\n", res); + + return 0; +}