UVa 12160 - Unlock the Lock

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/mobius_strip/article/details/81535378

题目

开密码锁，有R个按钮，每次按对应的按钮，密码会增加对应的值，已知初始状态和开锁的密码，问最少的按钮次数。

分析

最短路，bfs。直接利用bfs搜索即可。

说明

1000题了，✿✿ヽ(°▽°)ノ✿
还要考ieltso(╯□╰)o

#include <stdio.h>
#include <stdlib.h>

int button[11];
int queue[10001];
int visit[10001] = {0};
int bfs(int L, int U, int R)
{
    for (int i = 0; i < 10000; ++ i) {
        visit[i] = 0;
    }

    int head = 0, tail = 1;
    queue[0] = L;
    visit[L] = 1;
    while (head < tail) {
        int now = queue[head ++];
        if (now == U) {
            return visit[now] - 1;
        }
        for (int i = 0; i < R; ++ i) {
            int New = (now + button[i])%10000;
            if (!visit[New]) {
                visit[New] = visit[now] + 1;
                queue[tail ++] = New;
            }
        }
    }
    return -1;
}

int main()
{
    int L, U, R, cases = 1;
    while (~scanf("%d%d%d", &L, &U, &R) && L+U+R) {
        for (int i = 0; i < R; ++ i) {
            scanf("%d", &button[i]);
        }

        printf("Case %d: ", cases ++);
        int ans = bfs(L, U, R);
        if (ans != -1) {
            printf("%d\n", ans);
        }else {
            printf("Permanently Locked\n");
        }
    }

    return 0;
}