ny 58 最少步数 (BFS)

题目：http://acm.nyist.net/JudgeOnline/problem.php?pid=58

就是一道简单的BFS 练习练习搜索，一次AC

#include <iostream>
#include <vector>
#include <cstring>
#include <cstdio>

using namespace std;

int a[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
                };
bool bool_judge[9][9];
typedef struct point
{
    int x,y,t;
    point()
    {
        x = -1; y = -1; t = -1;
    }
}point;

vector<point>v;
vector<point>::iterator p;
point q;

void init()
{
    memset(bool_judge,false,sizeof(bool_judge));
   /* for(int i = 0; i < 9; i++)
    {
        for(int j = 0; j < 9; j++)
            printf("%d ",a[i][j]);
        printf("
");
    }*/
}
void add(point k,int t)
{
    if(k.x-1 >= 0 && a[k.x - 1][k.y] == 0 && bool_judge[k.x - 1][k.y] == false)
    {
        q.x = k.x - 1,q.y = k.y,q.t = t;
        v.push_back(q);
        bool_judge[k.x - 1][k.y] = true;
    }

    if(k.x + 1 <= 8 && a[k.x+1][k.y] == 0 && bool_judge[k.x+1][k.y] == false)
    {
        q.x = k.x + 1,q.y = k.y,q.t = t;
        v.push_back(q);
        bool_judge[k.x + 1][k.y] = true;
    }

    if(k.y - 1 >= 0 && a[k.x][k.y - 1] == 0 && bool_judge[k.x][k.y - 1] == false)
    {
         q.x = k.x,q.y = k.y - 1,q.t = t;
        v.push_back(q);
        bool_judge[k.x][k.y - 1] = true;
    }

    if(k.y + 1 <= 8 && a[k.x][k.y+1] == 0 && bool_judge[k.x][k.y + 1] == false)
    {
         q.x = k.x,q.y = k.y + 1,q.t = t;
        v.push_back(q);
        bool_judge[k.x][k.y + 1] = true;
    }
}

int BFS(int x2,int y2)
{
    while(v.empty() != true)
    {
        q = v[0];
        p = v.begin();
        v.erase(p);
        //printf("chu %d  %d
",q.x,q.y);
        if(q.x == x2 && q.y == y2)
        {
            return q.t;
        }
        add(q,++q.t);
    }
    return 0;
}
int main()
{
    init();
    int n;
    scanf("%d",&n);
    int x1,y1,x2,y2;
    while(n--)
    {
        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
        q.x = x1,q.y = y1,q.t = 0;
        v.push_back(q);
        bool_judge[x1][y1] = true;
        int sum = BFS(x2,y2);
        printf("%d
",sum);
        v.clear();
        init();
    }
    return 0;
}