CodeForces #549 Div.2 C Queen

#include <iostream>
#include <stdio.h>
#include <algorithm>

using namespace std;

#define MAX 100000

struct Node
{
    int value;
    int c;
    int next;
}edge[MAX+5];
int pos;
int head[MAX+5];
int a[MAX+5];
int aa=0;
int n;
void Init()
{
    for(int i=1;i<=n;i++)
        head[i]=-1;
    pos=0;
}

void add(int x,int y,int c)
{
    edge[pos].value =y;
    edge[pos].c = c;
    edge[pos].next = head[x];
    head[x]=pos++;
}

void dfs(int root,int c)
{
    int x=head[root];
    
    int t=0;
    while(x!=-1)
    {
       if(!(c==1&&edge[x].c==1))
       {
           t=1;
       }
        
        dfs(edge[x].value,edge[x].c);
        x=edge[x].next;
    }
    
    if(t==0&&c==1)
        a[aa++]=root;
}

int main()
{
    scanf("%d",&n);
    Init();
    int p,c;
    int root=0;
    for(int i=1;i<=n;i++)
    {
        scanf("%d%d",&p,&c);
        if(p==-1)
        {
            root=i;
            continue;
        }
        add(p,i,c);
    }
    
    dfs(root,0);
    
    if(aa==0)
        printf("-1\n");
    else
    {
        sort(a,a+aa);
        for(int i=0;i<aa;i++)
        {
            if(i!=aa-1)
                printf("%d ",a[i]);
            else
                printf("%d\n",a[i]);
        }
    }
    return 0;
}