Language: C++

#line 2 "header.hpp"

//%snippet.set('header')%
//%snippet.fold()%
#ifndef HEADER_H
#define HEADER_H

// template version 2.0
using namespace std;
#include <bits/stdc++.h>

// varibable settings
const long long INF = 1e18;
template <class T> constexpr T inf = numeric_limits<T>::max() / 2.1;

#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for (ll i = (ll)(a); i < (ll)(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define _rrep(i, n) rrepi(i, 0, n)
#define rrepi(i, a, b) for (ll i = (ll)((b)-1); i >= (ll)(a); --i)
#define r_rep(...) _overload3(__VA_ARGS__, rrepi, _rrep, )(__VA_ARGS__)
#define each(i, a) for (auto &&i : a)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define mt(...) make_tuple(__VA_ARGS__)
#define ub upper_bound
#define lb lower_bound
#define lpos(A, x) (lower_bound(all(A), x) - A.begin())
#define upos(A, x) (upper_bound(all(A), x) - A.begin())
template <class T> inline void chmax(T &a, const T &b) { if ((a) < (b)) (a) = (b); }
template <class T> inline void chmin(T &a, const T &b) { if ((a) > (b)) (a) = (b); }
template <typename X, typename T> auto make_table(X x, T a) { return vector<T>(x, a); }
template <typename X, typename Y, typename Z, typename... Zs> auto make_table(X x, Y y, Z z, Zs... zs) { auto cont = make_table(y, z, zs...); return vector<decltype(cont)>(x, cont); }

#define divceil(a, b) ((a) + (b)-1) / (b)
#define is_in(x, a, b) ((a) <= (x) && (x) < (b))
#define uni(x) sort(all(x)); x.erase(unique(all(x)), x.end())
#define slice(l, r) substr(l, r - l)

typedef long long ll;
typedef long double ld;
using vl = vector<ll>;
using vvl = vector<vl>;
using pll = pair<ll, ll>;

template <typename T>
using PQ = priority_queue<T, vector<T>, greater<T>>;
void check_input() { assert(cin.eof() == 0); int tmp; cin >> tmp; assert(cin.eof() == 1); }

#if defined(PCM) || defined(LOCAL)
#else
#define dump(...) ;
#define dump_1d(...) ;
#define dump_2d(...) ;
#define cerrendl ;
#endif

#endif /* HEADER_H */
//%snippet.end()%
#line 2 "solve.cpp"
template<class T=ll> using vec = vector<T>;
struct Fast { Fast() { std::cin.tie(0); ios::sync_with_stdio(false); } } fast;


// snippet:unionfind_with_potential {{{
template<class Pot = ll>  // Pot: Abel
struct UnionFind {
    vector<int> par;   // par[x]: parent of x. if root, -size.
    int gcount;         // count of groups
    vector<Pot>  diff;
    UnionFind() {}
    UnionFind(int _n, Pot SUM_UNITY = 0) : par(_n, -1), gcount(_n), diff(_n, SUM_UNITY) {}
    bool merge(int x, int y, Pot d) { /*{{{*/
        // d:= wight(y) - weight(x)
        int rx = root(x);
        int ry = root(y);
        if (rx != ry) {
            if (par[ry] >= par[rx]) {
                par[rx] += par[ry];
                par[ry] = rx;
                diff[ry] = diff[x] + d + (-diff[y]);
            }
            else{
                par[ry] += par[rx];
                par[rx] = ry;
                diff[rx] = (-diff[x]) + (-d) + diff[y];
            }
            gcount--;
        }
        else{
            if (weight(y) + (-weight(x)) != d){
                throw invalid_argument("contradiction exist");
            }
        }
        return rx != ry;
    } /*}}}*/
    int root(int x) {/*{{{*/
        if (is_root(x)){
            return x;
        }
        else{
            int r = root(par[x]);
            par[x] = r;
            diff[x] += diff[r];
            return par[x];
        }
    }/*}}}*/
    Pot weight(int x){/*{{{*/
        root(x); // 経路圧縮
        return diff[x];
    }/*}}}*/
    bool is_root(int x) { return par[x] < 0; }
    bool same(int x, int y) { return root(x) == root(y); }
    int size(int x) { return -par[root(x)]; }
#if defined(PCM) || defined(LOCAL)  // {{{
    friend ostream& operator<<(ostream& os, UnionFind& uf) {
        map<int, vector<int>> group;
        rep(i, sz(uf.par)) { group[uf.root(i)].pb(i); }
        os << endl;
        each(g, group) { os << g << endl; }
        return os;
    }
#endif  // }}}
};
// snippet:unionfind_with_potential }}}

int solve() {
    ll n,m;cin>>n>>m;

    UnionFind<ll> uf<>(n);
    try{
        rep(i, m){
            ll l,r,d;cin>>l>>r>>d;
            l--;r--;
            uf.merge(l, r, d);
        }
    }
    catch (invalid_argument){
        cout << "No" << endl;
        return 0;
    }
    cout << "Yes" << endl;
    return 0; 
}


int main(){/*{{{*/
    solve();
    check_input();
    return 0;
}/*}}}*/


Compiler output:
solve.cpp: In function 'int solve()':
solve.cpp:71:21: error: expected initializer before '<' token
solve.cpp:76:13: error: 'uf' was not declared in this scope; did you mean 'ub'?