#include<stdio.h>
#include<string.h>
#include<iostream>
#include<queue>
using namespace std;

int step[100010];
int vis[100010];
queue <int> q;

int BFS(int n, int k)
{
    int i;
    int head, next;
    q.push(n);
    step[n]=0;
    vis[n]=1;

    while(!q.empty())
    {
        head=q.front();
        q.pop();
        for(i=0; i<3; i++)
        {
            if(i==0) next=head-1;
            else if(i==1) next=head+1;
            else next=head*2;

            if(next<0 || next>100000) continue;
            if(!vis[next])
            {
                q.push(next);
                step[next]=step[head]+1;
                vis[next]=1;
            }
            if(next==k) return step[next];
        }
    }
}

int main()
{
    int n, k;

    while(scanf("%d%d", &n, &k)!=EOF)
    {
        memset(step, 0, sizeof(step));
        memset(vis, 0, sizeof(vis));

        while(!q.empty()) q.pop();

        if(n>=k)
            printf("%d\n", n-k);
        else
            printf("%d\n", BFS(n, k));
    }
}

• Re:第一次理解广搜 贴个代码 (1186) guiguai 2017-12-03 20:43:18
• Re:第一次理解广搜 贴个代码 (1186) guiguai 2017-12-03 20:43:19