题目链接：https://vjudge.net/contest/353062#problem/F

题目大意：给你若干个区间和区间对应的值，求冲突的区间

带权并查集果题

#include<set>
#include<map>
#include<stack>
#include<queue>
#include<cmath>
#include<cstdio>
#include<cctype>
#include<string>
#include<vector>
#include<climits>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#define endl '\n'
#define max(a, b) (a > b ? a : b)
#define min(a, b) (a < b ? a : b)
#define zero(a) memset(a, 0, sizeof(a))
#define INF(a) fill(a, a+maxn, INF);
#define IOS ios::sync_with_stdio(false)
#define _test printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n")
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef pair<double, int> P2;
const double pi = acos(-1.0);
const double eps = 1e-7;
const ll MOD =  1000000007LL;
const int INF = 0x3f3f3f3f;
const int _NAN = -0x3f3f3f3f;
const double EULC = 0.5772156649015328;
const int NIL = -1;
template<typename T> void read(T &x){
    x = 0;char ch = getchar();ll f = 1;
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch=getchar();}
    while(isdigit(ch)){x = x*10+ch-48;ch=getchar();}x*=f;
}
const int maxn = 2e5+10;
int p[maxn], dis[maxn];
int __find(int root) {
    if (root != p[root]) {
        int t = p[root];
        p[root] = __find(p[root]);
        dis[root] += dis[t];
    }
    return p[root];
}
int main(void) {
    IOS;
    int n, m;
    while(cin >> n >> m) {
        int ans = 0;
        zero(dis);
        for (int i = 0; i<=n; ++i)
            p[i] = i;
        while(m--) {
            int l, r, d;
            cin >> l >> r >> d;
            --l;
            int r1 = __find(l);
            int r2 = __find(r);
            if (r1 == r2 && dis[l]-dis[r] != d)
                ++ans;
            else if (r1 != r2) {
                p[r1] = r2;
                dis[r1] = dis[r]-dis[l]+d;
            }
        }
        cout << ans << endl;
    }
    return 0;
}