[kuangbin带你飞]专题一 简单搜索 -C - Catch That Cow
Catch That CowTime Limit: 2000MS Memory Limit: 65536KTotal Submissions: 70104 Accepted: 22060DescriptionFarmer John has been informed of the location of a fugitiv
Time Limit: 2000MS | Memory Limit: 65536K | |
Total Submissions: 70104 | Accepted: 22060 |
Description
Farmer John has been informed of the location of a fugitive cow and wants to catch her immediately. He starts at a point N (0 ≤ N ≤ 100,000) on a number line and the cow is at a point K (0 ≤ K ≤ 100,000) on the same number line. Farmer John has two modes of transportation: walking and teleporting.
* Walking: FJ can move from any point X to the points X - 1 or X + 1 in a single minute
* Teleporting: FJ can move from any point X to the point 2 × X in a single minute.
If the cow, unaware of its pursuit, does not move at all, how long does it take for Farmer John to retrieve it?
Input
Output
Sample Input
5 17
Sample Output
4
Hint
分析:简单的bfs,水题.
code:
#include <cstdio>
#include <queue>
#include <iostream>
#include <cstring>
using namespace std;
typedef long long ll;
typedef struct{
int x,time;
}data;
int vis[100005],ex;
data star;
void bfs()
{
queue <data> q;
q.push(star);
while(q.size())
{
data now=q.front(),nex;
q.pop();
int a=now.x+1;
if(now.x==ex)
{
cout<<now.time<<endl;
return;
}
if( 0 <=a && a <= 100000 && vis[a]==0 )
{
nex.time=now.time+1;
nex.x=a;
vis[a]=1;
q.push(nex);
}
a=now.x-1;
if( 0 <=a && a <= 100000 && vis[a]==0 )
{
nex.time=now.time+1;
nex.x=a;
vis[a]=1;
q.push(nex);
}
a=now.x*2;
if( 0 <=a && a <= 100000 && vis[a]==0 )
{
nex.time=now.time+1;
nex.x=a;
vis[a]=1;
q.push(nex);
}
}
}
int main(void)
{
scanf("%d %d",&star.x,&ex);
star.time=0;
vis[star.x]=1;
bfs();
}
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