历经各种玄学错误,终于改好了
C++ 代码
//#pragma GCC optimize(3,"inline","Ofast","fast-math","no-stack-protector","unroll-loops")
//#pragma GCC target("sse","sse2","sse3","sse4","avx","avx2","popcnt")
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<vector>
#define RG register
#define ll long long
#define INF 0x3f3f3f3f
using namespace std;
const int N=2e6+10;
int n,m,cnt,num,ans;
int pre[N];
struct nkl
{
int x,y,z;
}e[N];
inline int find(int x)
{
if(x==pre[x]) return x;
return pre[x]=find(pre[x]);
}
int main()
{
scanf("%d%d",&n,&m);
for (int i=n*m;i>=0;i--) pre[i]=i;
int x1,y1,x2,yy;
while(scanf("%d%d%d%d",&x1,&y1,&x2,&yy)!=EOF)
{
x1=(x1-1)*m+y1,x2=(x2-1)*m+yy;
int k=find(x1),l=find(x2);
if(k!=l) num++;
pre[k]=l;
}
for (int i=2;i<=n;i++)
for (int j=1;j<=m;j++)
{
int x=(i-1)*m+j,y=(i-2)*m+j;
e[++cnt].x=x,e[cnt].y=y;
e[cnt].z=1;
}
for (int i=1;i<=n;i++)
for (int j=2;j<=m;j++)
{
int x=(i-1)*m+j,y=x-1;
e[++cnt].x=x,e[cnt].y=y;
e[cnt].z=2;
}
for (int i=1;i<=cnt;i++)
{
int k=find(e[i].x),l=find(e[i].y);
if(k==l) continue;
num++;
pre[k]=l;
ans+=e[i].z;
if(num==n*m-1) break;
}
printf("%d\n",ans);
return 0;
}