Submission #1034814

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define watch(a) { cout << #a << " = " << a << endl; }
template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }
template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }
template<class T> void operator>> (istream& ist, vector<T>& vs) { for(auto& e: vs) cin >> e; }

typedef long long ll;
int const inf = 1<<29;

namespace tree {
struct union_find {
  vector<int> par, rank, size;
  int compnum;

  union_find(int N) {
    compnum = N;
    par.resize(N), rank.resize(N), size.resize(N);
    for(int i=0; i<N; i++) {
      par[i] = i;
      rank[i] = 0;
      size[i] = 1;
    }
  }

  int root(int x) {
    return par[x] == x ? x : par[x] = root(par[x]);
  }

  void unite(int x, int y) {
    x = root(x), y = root(y);
    if(x == y) return;
    if(rank[x] < rank[y]) {
      par[x] = y, size[y] += size[x];
    } else {
      par[y] = x, size[x] += size[y];
      if(rank[x] == rank[y]) rank[x]++;
    }
    compnum--;
  }

  int operator[](int x) { return root(x); }
  void operator()(int x, int y) { return unite(x, y); }

  bool same(int x, int y) { return root(x) == root(y); }
  int size_of(int x) { return size[root(x)]; }
  int num_of_comps() { return compnum; }
};
}

int main() {

  int N, M; cin >> N >> M;
  vector<tuple<int, int, int>> es;
  rep(i, M) {
    int a, b, c; scanf("%d%d%d", &a, &b, &c);
    a--, b--;
    es.emplace_back(c, a, b);
  }

  sort(es.begin(), es.end());

  int Q; cin >> Q;
  rep(i, Q) {
    int s, t; cin >> s >> t; s--, t--;
    tree::union_find uf(N);
    uf.unite(s, t);
    ll ans = 0;
    rep(k, M) {
      int a, b, c; tie(c, a, b) = es[k];
      if(!uf.same(a, b)) {
        uf.unite(a, b);
        ans += c;
      }
    }

    cout << ans << endl;
  }
  
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:63:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     int a, b, c; scanf("%d%d%d", &a, &b, &c);
                                             ^

Judge Result