CodeForces 520B Two Buttons bfs+优先队列

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int maxn  = 10010;
const int inf = 0x7fffffff;
int vis[maxn*10] ;
int  n,m;int ans = inf;
struct node
{
    int step ;
    int value ;
};
struct cmp{
    bool operator()(struct node &a,struct node &b)
    {
        return a.step>b.step;
    }
};
void bfs()
{
    priority_queue<struct node,vector<struct node>,cmp> que;
    struct node first = {0,n};
    que.push(first);
    vis[n] = 1;
    vis[0] = 1;
    while(que.size())
    {
        struct node now = que.top();
        que.pop();
        if(now.value == m)
        {
            printf("%d\n",now.step);
            break;
        }
        if((2*now.value >= 0) && (2*now.value <= max(2*n,2*m)) &&(!vis[now.value*2]))
        {
            struct node next = {now.step+1,now.value*2};
            vis[now.value*2] = 1;
            que.push(next);
        }
        if(now.value - 1 >= 0 && now.value - 1 <= max(2*n , 2*m) && !vis[now.value - 1])
        {
            struct node next = {now.step+1,now.value-1};
            vis[now.value-1] = 1;
            que.push(next) ;
        }
    }
}
int main()
{
   scanf("%d%d",&n,&m);
   memset(vis,0,sizeof(vis));
   bfs();
   return 0;
}

CodeForces 520B Two Buttons bfs+优先队列

原文：http://blog.csdn.net/cq_pf/article/details/44628795