信息学奥赛一本通T1437-扩散 - C语言网 (dotcpp.com)

#include <iostream>
#include <algorithm>
using namespace std;
#define int long long
const int N=2e2;
int n;
struct node{int x,y;
}a[N];
int fa[N];
int dist[N][N];//记录两坐标间的曼哈顿距离
int find(int x)
{if(fa[x]==x)return x;elsereturn fa[x]=find(fa[x]);
}
void Union(int x,int y)
{x=find(x);y=find(y);if(x!=y)fa[x]=y;
}
bool solve(int mid)
{for(int i=1;i<=n;i++)//初始化并查集fa[i]=i;for(int i=1;i<n;i++){for(int j=i+1;j<=n;j++){if(dist[i][j]<=mid*2)//两点间的距离能在mid内连通Union(i,j);}}int cnt=0;for(int i=1;i<=n;i++){if(fa[i]==i)cnt++;if(cnt==2)//有2个以上就不符合return false;}return true;
}
signed main()
{cin>>n;for(int i=1;i<=n;i++)cin>>a[i].x>>a[i].y;for(int i=1;i<n;i++){for(int j=i+1;j<=n;j++){dist[i][j]=dist[j][i]=abs(a[i].x-a[j].x)+abs(a[i].y-a[j].y);//两点的曼哈顿距离}}int l=0,r=1e9;while(l<r)//二分答案--时间{int mid=(l+r)/2;if(solve(mid))r=mid;elsel=mid+1;}cout<<l;return 0;
}