BZOJ 2054 疯狂的馒头

Posted 2020-08-19 ziliuziliu

并查集把染过色的并在一起。倒着染色。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 10000050
using namespace std;
int n,m,l[maxn],r[maxn],father[maxn/10],p,q,col[maxn/10];
int getfather(int x)
{
    if (x!=father[x]) father[x]=getfather(father[x]);
    return father[x];
}
void unionn(int x,int y)
{
    if ((!col[x]) && (!col[y])) return;
    int f1=getfather(x),f2=getfather(y);
    father[f1]=f2;
}
int main()
{
    scanf("%d%d%d%d",&n,&m,&p,&q);
    for (int i=1;i<=m;i++)
    {
        l[i]=(i*p+q)%n+1;r[i]=(i*q+p)%n+1;
        if (l[i]>r[i]) swap(l[i],r[i]);
    }
    for (int i=1;i<=n;i++) father[i]=i;
    for (int i=m;i>=1;i--)
    {
        int now=l[i];
        if (col[now]) now=getfather(now)+1;
        while (now<=r[i])
        {
            unionn(now-1,now);unionn(now,now+1);
            col[now]=i;
            now++;
            if (col[now]) now=getfather(now)+1;
        }
    }
    for (int i=1;i<=n;i++) printf("%d\n",col[i]);
    return 0;
}