P2921 [USACO08DEC]在农场万圣节Trick or Treat on the Farm

#include<bits/stdc++.h>
using namespace std;
inline  int read(){
    int sum=0,x=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-')
            x=0;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
        sum=(sum<<1)+(sum<<3)+(ch^48),ch=getchar();
    return x?sum:-sum;
}
inline void write(int x){
    if(x<0)
        putchar('-'),x=-x;
    if(x>9)
        write(x/10);
    putchar(x%10+'0');
}
const int M=1e5+5;
int nex[M];
int color[M];//在图上记录走过的标记；
int dfn[M];//时间戳
int minc[M];//记录当前换的大小；
int incycle[M];//记录当前牛什么时候进入环
int ma(int x,int y){
    return x>y?x:y;
}
int main(){
    int n=read();
    for(int i=1;i<=n;i++)
        nex[i]=read();
    for(int i=1;i<=n;i++){
        for(int j=i,cnt=0;;cnt++,j=nex[j]){
            if(!color[j]){
                color[j]=i;
                dfn[j]=cnt;
            }
            else if(color[j]==i){
                write(cnt);
                putchar('
');
                minc[i]=cnt-dfn[j];
                incycle[i]=dfn[j];
                break;
            }
            else{
                minc[i]=minc[color[j]];
                incycle[i]=cnt+ma(incycle[color[j]]-dfn[j],0);
                write(minc[i]+incycle[i]);
                putchar('
');
                break;
            }
        }
    }
    return 0;
}