标签：empty reac imm The input 剪枝 暴力 size lang
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?
5 17
4
#include <algorithm>
#include <bitset>
//#include <bits/extc++.h>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
using namespace std;
//using namespace __gnu_pbds
#define ll long long
#define maxn 105
int s, e, step[100005];
bool vis[100005];
void bfs()
{
queue<int> q;
q.push(s);
vis[s] = 0;
step[s] = 0;
while (!q.empty())
{
int now = q.front();
q.pop();
int next = now + 1;
if (next <= e && vis[next])
{
vis[next] = false;
step[next] = step[now] + 1;
q.push(next);
}
if (next == e)
{
return;
}
next = now - 1;
if (next >= 0 && vis[next])
{
vis[next] = false;
step[next] = step[now] + 1;
q.push(next);
}
if (next == e)
{
return;
}
next = now << 1;
if ((next <= e || next - e + 1 < e - now) && next <= 100000 && vis[next])
{
vis[next] = false;
step[next] = step[now] + 1;
q.push(next);
}
if (next == e)
{
return;
}
}
}
int main()
{
while (~scanf("%d%d", &s, &e))
{
memset(vis, true, sizeof(vis));
if (s >= e)
{
printf("%d\n", s - e); //剪枝
}
else
{
bfs();
printf("%d\n", step[e]);
}
}
return 0;
}
标签：empty reac imm The input 剪枝 暴力 size lang
原文地址：https://www.cnblogs.com/whitabbit/p/12228477.html
