hdu 3038 How Many Answers Are Wrong 带权并查集

题意：给出n个数m个关系，其中A，B，S,表示从下标A到B的数的总和是S（n个数具体是什么不知道），问有多少个冲突关系。

将“下标A到B的数的总和是S”转换成，下标B比A-1的的数大S,这样题目就变成hdu 3047 解决方法同

#include <map>
#include <set>
#include <queue>
#include <stack>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
#define pi acos(-1.0)
#define eps 1e-8
#define asd puts("sdasdasdasdasd");
typedef long long ll;
const int inf = 0x3f3f3f3f;
const int N = 200050;

int r
, fa
;
int n, m;

void init()
{
	for( int i = 1; i <= n; ++i )
	{
		fa[i] = i; 
		r[i] = 0;
	}
}

int dfs( int x )
{
	if ( x == fa[x] )
		return x;
	int ani = fa[x];
	fa[x] = dfs( fa[x] );
	r[x] += r[ani];
	return fa[x];
}

bool Union( int a, int b, int c )
{
	int x = dfs( a );
	int y = dfs( b );
	if( x == y )
	{
		if( r[a] + c == r[b] )
			return 1;
		else
			return 0;
	}
	fa[y] = x;
	r[y] = r[a] + c - r[b];
	return 1;
}

int main()
{
	while( ~scanf("%d%d", &n, &m) )
	{
		init();
		int cnt = 0;
		int a, b, x;
		while ( m-- )
		{
			scanf("%d%d%d", &a, &b, &x );
			if( !Union( a-1, b, x ) )
				cnt++;
		}
		printf("%d\n", cnt);
	}
	return 0;
}