Submission #6072235

---

Source Code Expand

#include<bits/stdc++.h>
#define REP(x,y,z) for(int x=y;x<=z;x++)
#define MSET(x,y) memset(x,y,sizeof(x))
#define M 100005
using namespace std;
class DSJ {
public:
    int ngroups;
    vector<int> fa,sz;
    DSJ() {}
    DSJ(int _n) {
        ngroups = _n;
        fa = vector<int> (_n+1);
        sz = vector<int> (_n+1, 1);
        REP(i,0,_n) fa[i] = i;
    }
    int find(int x) {
        return x==fa[x] ? x : fa[x]=find(fa[x]);
    }
    int size(int x) {
        return sz[find(x)];
    }
    void con(int x,int y) {
        x = find(x);
        y = find(y);
        if (x==y) return;
        fa[x] = y;
        sz[y] += sz[x];
        ngroups--;
    }
    int groups() {
        return ngroups;
    }
}dsj;
int n,px[M],py[M];
vector<int> xs[M], ys[M];
int main()
{
    while (~scanf("%d", &n)) {
        REP(i,0,M-1) {
            xs[i].clear();
            ys[i].clear();
        }
        REP(i,1,n) {
            int x,y;
            scanf("%d %d",&x,&y);
            xs[x].push_back(i);
            ys[y].push_back(i);
            px[i] = x;
            py[i] = y;
        }

        dsj = DSJ(n);
        REP(i,0,M-1) REP(j,1,(int)xs[i].size()-1) dsj.con(xs[i][j-1], xs[i][j]);
        REP(i,0,M-1) REP(j,1,(int)ys[i].size()-1) dsj.con(ys[i][j-1], ys[i][j]);

        vector<int> childs[M];
        long long ans = 0;
        REP(i,1,n) childs[dsj.find(i)].push_back(i);
        REP(i,1,n) if(dsj.find(i)==i) {
            set<int> xx, yy;
            for (int j:childs[i]) {
                xx.insert(px[j]);
                yy.insert(py[j]);
            }

            ans += (long long)xx.size() * yy.size();
        }
        printf("%lld\n", ans-n);
    }
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:46:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %d",&x,&y);
                                 ^

Judge Result