Submission #996580

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Source Code Expand

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

typedef pair<int,int> ii;
typedef pair<long long, ii> iii;

class UnionFindDS{
private:
    vector<int> p, sz;   // parent, size
    int num;
public:
    UnionFindDS(int N){
        p.assign(N,0); for (int i = 0; i < N; i++) p[i] = i;
        sz.assign(N,1); num = N;
    }
    int numSets(){ return num; }
    int findSet(int i){ return p[i] == i ? i : p[i] = findSet(p[i]); }
    int sizeSet(int i){ return sz[findSet(i)]; }
    bool isSameSet(int i, int j){ return findSet(i) == findSet(j); }
    void unionSet(int i, int j){
        if ((i = findSet(i)) == (j = findSet(j))) return;
        
        num--;
        p[j] = i; sz[i] += sz[j];
    }
};

int N, M, Q;
vector<iii> edge;

int main() {

    scanf("%d%d", &N, &M);
    for (int i = 0, u, v; i < M; i++) {
        long long w;
        scanf("%d%d%lld", &u, &v, &w);

        edge.push_back(iii(w, ii(u, v)));
    }

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

    scanf("%d", &Q);
    for (int i = 0, u, v; i < Q; i++) {
        scanf("%d%d", &u, &v);

        UnionFindDS uf(N+1);
        uf.unionSet(u, v);

        long long ans = 0;
        for (int i = 0; i < edge.size(); i++) {
            long long w = edge[i].first;
            long long u = edge[i].second.first;
            long long v = edge[i].second.second;

            if (uf.isSameSet(u, v)) continue;

            uf.unionSet(u, v); ans += w;
        }

        printf("%lld\n", ans);
    }

    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:33:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &N, &M);
                          ^
./Main.cpp:36:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%lld", &u, &v, &w);
                                      ^
./Main.cpp:43:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &Q);
                    ^
./Main.cpp:45:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &u, &v);
                              ^

Judge Result