种类并查集 食物链

#include <stdio.h>
#include <iostream>
#include <stack>
#include <string>
#include <set>
#include <memory.h>
#include <math.h>
#include <algorithm>
#include <queue>
#include <unordered_set>
using namespace std;
int parent[50005], group[50005], N, K, cnt, d;
int FindParent( int i )
{
    if( i == parent[i] )
    {
        return i;
    }
    int temp = FindParent( parent[i] );
    group[i] = ( group[i] + group[parent[i]] )%3;
    parent[i] = temp;
    return temp;
}
void uni( int x, int y )
{
    int pax = FindParent(x);
    int pay = FindParent(y);
    if( pax == pay )
    {
        if( d == 1 && group[x] != group[y] )
        {
            cnt++;
        }
        else if( d == 2 && group[x] == 1 && group[y] != 0 )
        {
            cnt ++;
        }
        else if( d == 2 && group[x] == 2 && group[y] != 1 )
        {
            cnt++;
        }
        else if( d == 2 && group[x] == 0 && group[y] != 2 )
        {
            cnt++;
        }
    }
    else
    {
        parent[pax] = pay;
        if( d == 1 )
        {
            group[pax] = ( group[y] - group[x] + 3 ) % 3;
        }
        else
        {
            group[pax] = (group[y] - group[x] + 4 ) % 3;
        }
    }
    return ;
}
int main()
{
    scanf("%d %d", &N, &K);
    for( int i = 1; i <= N; i++ )
    {
        parent[i] = i;
        group[i] = 0;
    }
    cnt = 0;
    while( K-- )
    {
        int x,y;
        scanf("%d %d %d", &d, &x, &y);
        if( x > N || y > N || ( d == 2 && x == y ) )
        {
            cnt ++;
            continue;
        }
        uni(x, y);
    }
    printf("%d\n", cnt);
    return 0;
}

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转载自blog.csdn.net/xutian_curry/article/details/80380177
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