HDOJ 2717 Catch That Cow

http://acm.hdu.edu.cn/showproblem.php?pid=2717

基本BFS

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <queue>
using namespace std;
int N,K;
int degree[100002];
queue<int> Q;
void bfs()
{
    while(!Q.empty()){
        int cur=Q.front();
        Q.pop();
        if(cur==K)
            break;
        if(cur-1>=0&&degree[cur-1]==0){
            degree[cur-1]=degree[cur]+1;
            Q.push(cur-1);
        }
        if(cur+1<=100000&&degree[cur+1]==0){
            degree[cur+1]=degree[cur]+1;
            Q.push(cur+1);
        }
        if(cur*2<=100000&&degree[2*cur]==0){
            degree[2*cur]=degree[cur]+1;
            Q.push(2*cur);
        }
    }
}


int main()
{
    while(scanf("%d%d",&N,&K)!=EOF){
        int i;
        for(i=0;i<100002;i++){
            degree[i]=0;
        }
        while(!Q.empty())
            Q.pop();

        Q.push(N);
        bfs();
        printf("%d\n",degree[K]);
    }
}