Submission #1226418

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <functional>
#include <numeric>
#include <set>
#include <map>
#include <list>
#include <bitset>
#define debug(x) cout << #x << ": " << (x) << endl
using namespace std;

const double PI  = 3.141592653589793238463;
const int INF = 1000000007;

using ull = unsigned long long;
using ll = long long;

using Int = int;
using Double = double;

using P = pair<Int, Int>;
using V = vector<Int>;
using M = vector<V>;

struct UnionFind{
    V data;
    UnionFind(int size):
        data(size, -1){}
    bool unite(int x, int y){
        x = find(x);
        y = find(y);
        if(x == y){
            return false;
        }
        if(y < x){
            swap(x, y);
        }
        data[x] += data[y];
        data[y] = x;
        return true;
    }
    int find(int x){
        if(data[x] < 0){
            return x;
        }else{
            return data[x] = find(data[x]);
        }
    }
};

int solve(int n, int m, V& as, V& bs){
    UnionFind uf(n);
    for(int i = 0; i < m; i++){
        uf.unite(as[i] - 1, bs[i] - 1);
    }
    set<int> gs;
    for(int i = 0; i < n; i++){
        gs.insert(uf.find(i));
    }
    return gs.size() - 1;
}

int main(int argc, char* argv[]){
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;
    V as(m), bs(m);
    for(int i = 0; i < m; i++){
        // cin >> as[i] >> bs[i];
        scanf("%d %d", &as[i], &bs[i]);
    }

    cout << solve(n, m, as, bs) << "\n";

    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main(int, char**)’:
./Main.cpp:77:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &as[i], &bs[i]);
                                       ^

Judge Result