pku--3278 catch the cow(*2 +1 -1 顺序抓补)

#include "iostream"#include "math.h"#include "queue"using namespace std;long mark[210000];struct node{long num;long lev;};queue <node> seq;node BFS(node s, node e){node front,temp;memset(mark,0,sizeof(mark));seq.push(s);while(!seq.empty()){front=seq.front();if(front.num==e.num) return front;mark[front.num]=1;seq.pop(); if(!mark[front.num-1]&&front.num-1>=0&&front.num-1<=100000){temp.num=front.num-1;mark[front.num-1]=1;temp.lev=front.lev+1;seq.push(temp);}if(!mark[front.num+1]&&front.num+1>=0&&front.num+1<=100000) {temp.num=front.num+1;mark[front.num+1]=1;temp.lev=front.lev+1;seq.push(temp);}if(!mark[front.num * 2]&&front.num*2>=0 && front.num*2 <=100000){ temp.num=front.num*2;mark[front.num*2]=1;temp.lev=front.lev+1;seq.push(temp);}}return front;}int main(){long a,b; node start,end,res;while(scanf("%ld %ld",&a,&b)!=EOF){while(!seq.empty()) seq.pop(); start.num=a;start.lev=0;end.num=b; res=BFS(start,end);printf("%ld/n",res.lev);}return 0;}