南阳oj-58 最少步数

最少步数

南阳oj-58

简单的bfs题目

#include <stdio.h>
#include <string.h>

int map[9][9]={
    {1,1,1,1,1,1,1,1,1},
    {1,0,0,1,0,0,1,0,1},
    {1,0,0,1,1,0,0,0,1},
    {1,0,1,0,1,1,0,1,1},
    {1,0,0,0,0,1,0,0,1},
    {1,1,0,1,0,1,0,0,1},
    {1,1,0,1,0,1,0,0,1},
    {1,1,0,1,0,0,0,0,1},
    {1,1,1,1,1,1,1,1,1}
};

int visit[9][9], k;
int pre[1000];
int dir[4][2]={{-1,0},{1,0},{0,-1},{0,1}};

struct cam{
    int x;
    int y;
}list[1000];

int go(int x, int y)
{
    if(0 <= x && x < 9 && 0 <= y && y < 9 && map[x][y] == 0)
        return 1;
    return 0;
}

int print(int x, int sum)
{
    int t;
    t = pre[x];
    if(t != 0)
        return 1 + print(t, sum);
    else{
        return 1;
    }
}

void bfs()
{
    int l;
    int x1, y1, x2, y2, n;
    int head, tail;
    int x, y, xx, yy;
    scanf("%d", &n);
    while(n--){
        scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
        if (x1 == x2 && y1 == y2){
            printf("0\n");
            continue;
        }
        memset(visit, 0, sizeof(visit));
        k = 0;
        head = 0;
        tail = 1;
        list[0].x = x1;
        list[0].y = y1;
        pre[0] = -1;
        while(head < tail){
            x = list[head].x;
            y = list[head].y;
            if(x == x2 && y == y2){
                l = print(head, 0);
                printf("%d\n", l);
                break;
            }
            for (int i = 0; i < 4; i++){
                xx = x + dir[i][0];
                yy = y + dir[i][1];
                if (!visit[xx][yy] && go(xx, yy)){
                    visit[xx][yy] = 1;
                    list[tail].x = xx;
                    list[tail].y = yy;
                    pre[tail] = head;
                    tail++;
                }
            }
            head++;
        }
    }
    return;
}

int main(void)
{
    bfs();
    return 0;
}