POJ 3278 Catch That Cow

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

BFS

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <queue>
using namespace std;
int N,K;
bool visited_flag[100002]={false};
bool check(int x)
{
    if(0<=x&&x<=100000)
        return true;
    return false;
}
void bfs()
{
    queue<int> Q;
    Q.push(N);
    Q.push(0);
    visited_flag[N]=true;
    int cur_pos;
    int cur_deep;
    while(!Q.empty()) {
        cur_pos=Q.front();
        Q.pop();
        cur_deep=Q.front();
        Q.pop();
        if(cur_pos==K) {
            printf("%d\n",cur_deep);
            return ;
        }
        if(check(cur_pos-1)&&!visited_flag[cur_pos-1]) {
            Q.push(cur_pos-1);
            Q.push(cur_deep+1);
            visited_flag[cur_pos-1]=true;
        }
        if(check(cur_pos+1)&&!visited_flag[cur_pos+1]) {
            Q.push(cur_pos+1);
            Q.push(cur_deep+1);
            visited_flag[cur_pos+1]=true;
        }
        if(check(2*cur_pos)&&!visited_flag[cur_pos*2]) {
            Q.push(cur_pos*2);
            Q.push(cur_deep+1);
            visited_flag[cur_pos*2]=true;
        }
    }
}
int main()
{
    while(scanf("%d%d",&N,&K)!=EOF) {
        memset(visited_flag,false,sizeof(visited_flag));
        bfs();
    }
    return 0;
}