ZOJ 3865 - Superbot(BFS)

来源：互联网发布：ubuntu获取arm gcc 编辑：程序博客网时间：2024/06/04 19:04

题目:

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=5477

题意:

给你一个n*m的地图,求出从@走到$的最小时间.使用按钮去控制人走的方向.

四个按钮的初始位置是(左,右,上,下).每p秒按钮会向右移动变成(下,左,右,上).

思路:

BFS.

vis[x][y][按钮方向][时间] 记录走过的位置.

在p秒来临前有三种: 按, 光标左移,光标右移

p秒时: 按后按钮动, 光标左移, 光标右移, 光标不动. (光标不动的情况时间要%4, 表示又回到了原来的位置.

AC.

#include <iostream>#include <cstdio>#include <queue>#include <cstring>using namespace std;int n, m, p;char mp[15][15];int r[5];int dx[] = {0, 0, -1, 1}, dy[] = {-1, 1, 0, 0};struct node {    int x, y, id, step;    node(int xx, int yy, int ii, int s) {        x = xx; y = yy; id = ii; step = s;    }//    bool operator < (const node&A) const {//        return step > A.step;//    }};queue<node> que;int edx, edy, stx, sty;bool vis[15][15][10][500];bool ok(int tx, int ty){    if(tx < 0 || tx >= n || ty < 0 || ty >= m        || mp[tx][ty] == '*') return false;    return true;}void rot(){    int t = r[3];    r[3] = r[2]; r[2] = r[1]; r[1] = r[0]; r[0] = t;}void bfs(){    memset(vis, 0, sizeof(vis));    int nx, ny, iid;    node no = node(stx, sty, 0, 0);    vis[stx][sty][0][0] = 1;    que.push(no);    while(que.size()) {        no = que.front(); que.pop();        if(no.x == edx && no.y == edy) {            printf("%d\n", no.step);            return;        }        int x = no.x, y = no.y, id = no.id, s = no.step;        s++;        if(s % p == 0) { //旋转            iid = (id-1+4)%4;//原位按            nx = x + dx[r[id]]; ny = y + dy[r[id]];            if(ok(nx, ny) && !vis[nx][ny][r[iid]][s]) {                no = node(nx, ny, iid, s);                vis[nx][ny][r[iid]][s] = 1;                que.push(no);            }            iid = (id-1+4)%4;//不动            if(!vis[x][y][r[iid]][s%4]) {                no = node(x, y, iid, s);                vis[x][y][r[iid]][s] = 1;                que.push(no);            }            iid = id;//右移            if(!vis[x][y][r[iid]][s]) {                no = node(x, y, iid, s);                vis[x][y][r[iid]][s] = 1;                que.push(no);            }            iid = (id-2+4)%4;//左移            if(!vis[x][y][r[iid]][s]) {                no = node(x, y, iid, s);                vis[x][y][r[iid]][s] = 1;                que.push(no);            }        }        else {//不旋转            nx = x + dx[r[id]]; ny = y + dy[r[id]];//按            if(ok(nx, ny) && !vis[nx][ny][r[id]][s] ) {                no = node(nx, ny, id, s);                vis[nx][ny][r[id]][s] = 1;                que.push(no);            }            iid = (id-1+4)%4;//左移            if(!vis[x][y][r[iid]][s]) {                no = node(x, y, iid, s);                vis[x][y][r[iid]][s] = 1;                que.push(no);            }            iid = (id+1+4)%4;//右移            if(!vis[x][y][r[iid]][s]) {                no = node(x, y, iid, s);                vis[x][y][r[iid]][s] = 1;                que.push(no);            }        }    }    printf("YouBadbad\n");    return;}int main(){//freopen("in", "r", stdin);    int T;    scanf("%d", &T);    while(T--) {        for(int i = 0; i < 4; ++i) r[i] = i;        while(que.size()) que.pop();        scanf("%d %d %d", &n, &m, &p);        for(int i = 0; i < n; ++i) {            scanf("%s", mp[i]);            for(int j = 0; j < m; ++j) {                if(mp[i][j] == '$') {                    edx = i; edy = j;                }                if(mp[i][j] == '@') {                    stx = i; sty = j;                }            }        }        //printf("%d %d\n", edx, edy);        bfs();    }    return 0;}

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