poj 3278 水bfs

点击打开链接</pre></p><p><pre name="code" class="cpp">#include <iostream>
#include <algorithm>
#include <queue>
#include <cstring>
using namespace std;
const int M=210000;
const int inf=100000;
struct Node{
int x;
int dist;
Node(int x1,int dist1):x(x1),dist(dist1)
{

}
};
queue<Node> q;
int visit[M];
int main()
{
int n,k;
memset(visit,0,sizeof(visit));
cin>>n>>k;
q.push(Node(n,0));
visit
=1;
while(!q.empty())
{
Node s=q.front();
q.pop();
if(s.x==k)
{
cout<<s.dist<<endl;
return 0;
}
else
{
if(s.x-1>=0&& !visit[s.x-1])
{
q.push(Node(s.x-1,s.dist+1));
visit[s.x-1]=1;
}
if(s.x+1<=inf&& !visit[s.x+1])
{
q.push(Node(s.x+1,s.dist+1));
visit[s.x+1]=1;
}
if(s.x*2<=inf && !visit[s.x*2])
{
q.push(Node(s.x*2,s.dist+1));
visit[s.x*2]=1;
}
}
}
return 0;
}