poj3278Catch That Cow（bfs)

http://poj.org/problem?id=3278

三次RE 以为是队列开小了 一直加大队列 忘记是标记数组的事了 改了判断条件 觉得队列不用开那么大 WA。。又开到100W AC..

#include<stdio.h>
#include<string.h>
struct node
{
    int x,num;
}q[1000001];
int f[1000010];
int p,d;
int main()
{
    int i,j,n,k,flag = 0;
    scanf("%d%d", &n,&k);
    p = 0;
    d = 1;
    q[d].num = 0;
    q[d++].x = n;
    while(p!=d)
    {
        p++;
        int g = q[p].x;
        if(g==k)
            break;
        if(g-1>=0&&!f[g-1])
        {
            q[d++].x = g-1;
            f[g-1] = 1;
            q[d-1].num = q[p].num+1;
        }
        if(g<100000&&!f[g+1])
        {
            q[d++].x = g+1;
            f[g+1] = 1;
            q[d-1].num = q[p].num+1;
        }
        if(2*g<=100000&&!f[2*g])
        {
            q[d++].x = 2*g;
            f[2*g] = 1;
            q[d-1].num = q[p].num+1;
        }
    }
    printf("%d\n",q[p].num);
}