mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-27 15:26:29 +08:00
e720aa2d24
* Sync recent changes to the revised Word. * Revised the preface chapter * Revised the introduction chapter * Revised the computation complexity chapter * Revised the chapter data structure * Revised the chapter array and linked list * Revised the chapter stack and queue * Revised the chapter hashing * Revised the chapter tree * Revised the chapter heap * Revised the chapter graph * Revised the chapter searching * Reivised the sorting chapter * Revised the divide and conquer chapter * Revised the chapter backtacking * Revised the DP chapter * Revised the greedy chapter * Revised the appendix chapter * Revised the preface chapter doubly * Revised the figures
47 lines
No EOL
1.2 KiB
C
47 lines
No EOL
1.2 KiB
C
/**
|
|
* File: climbing_stairs_backtrack.c
|
|
* Created Time: 2023-09-22
|
|
* Author: huawuque404 (huawuque404@163.com)
|
|
*/
|
|
|
|
#include "../utils/common.h"
|
|
|
|
/* 回溯 */
|
|
void backtrack(int *choices, int state, int n, int *res, int len) {
|
|
// 当爬到第 n 阶时，方案数量加 1
|
|
if (state == n)
|
|
res[0]++;
|
|
// 遍历所有选择
|
|
for (int i = 0; i < len; i++) {
|
|
int choice = choices[i];
|
|
// 剪枝：不允许越过第 n 阶
|
|
if (state + choice > n)
|
|
continue;
|
|
// 尝试：做出选择，更新状态
|
|
backtrack(choices, state + choice, n, res, len);
|
|
// 回退
|
|
}
|
|
}
|
|
|
|
/* 爬楼梯：回溯 */
|
|
int climbingStairsBacktrack(int n) {
|
|
int choices[2] = {1, 2}; // 可选择向上爬 1 阶或 2 阶
|
|
int state = 0; // 从第 0 阶开始爬
|
|
int *res = (int *)malloc(sizeof(int));
|
|
*res = 0; // 使用 res[0] 记录方案数量
|
|
int len = sizeof(choices) / sizeof(int);
|
|
backtrack(choices, state, n, res, len);
|
|
int result = *res;
|
|
free(res);
|
|
return result;
|
|
}
|
|
|
|
/* Driver Code */
|
|
int main() {
|
|
int n = 9;
|
|
|
|
int res = climbingStairsBacktrack(n);
|
|
printf("爬 %d 阶楼梯共有 %d 种方案\n", n, res);
|
|
|
|
return 0;
|
|
} |