增加C的贪心算法代码 (#726)

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linweibin 2023-09-09 16:28:44 +08:00 committed by GitHub
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commit c8e0c476bd
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3 changed files with 62 additions and 0 deletions

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@ -15,3 +15,4 @@ add_subdirectory(chapter_graph)
add_subdirectory(chapter_searching)
add_subdirectory(chapter_sorting)
add_subdirectory(chapter_backtracking)
add_subdirectory(chapter_greedy)

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@ -0,0 +1 @@
add_executable(coin_change_greedy coin_change_greedy.c)

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@ -0,0 +1,60 @@
/**
* File: coin_change_greedy.c
* Created Time: 2023-09-07
* Author: lwbaptx (lwbaptx@gmail.com)
*/
#include "../utils/common.h"
/* 零钱兑换:贪心 */
int coinChangeGreedy(int* coins, int size, int amt) {
// 假设 coins 列表有序
int i = size - 1;
int count = 0;
// 循环进行贪心选择,直到无剩余金额
while (amt > 0) {
// 找到小于且最接近剩余金额的硬币
while (i > 0 && coins[i] > amt) {
i--;
}
// 选择 coins[i]
amt -= coins[i];
count++;
}
// 若未找到可行方案,则返回 -1
return amt == 0 ? count : -1;
}
/* Driver Code */
int main() {
// 贪心:能够保证找到全局最优解
int coins1[6] = {1, 5, 10, 20, 50, 100};
int amt = 186;
int res = coinChangeGreedy(coins1, 6, amt);
printf("\ncoins = ");
printArray(coins1, 6);
printf("amt = %d\n", amt);
printf("凑到 %d 所需的最少硬币数量为 %d\n", amt, res);
// 贪心:无法保证找到全局最优解
int coins2[3] = {1, 20, 50};
amt = 60;
res = coinChangeGreedy(coins2, 3, amt);
printf("\ncoins = ");
printArray(coins2, 3);
printf("amt = %d\n", amt);
printf("凑到 %d 所需的最少硬币数量为 %d\n", amt, res);
printf("实际上需要的最少数量为 3 ,即 20 + 20 + 20\n");
// 贪心:无法保证找到全局最优解
int coins3[3] = {1, 49, 50};
amt = 98;
res = coinChangeGreedy(coins3, 3, amt);
printf("\ncoins = ");
printArray(coins3, 3);
printf("amt = %d\n", amt);
printf("凑到 %d 所需的最少硬币数量为 %d\n", amt, res);
printf("实际上需要的最少数量为 2 ,即 49 + 49\n");
return 0;
}