Submission #18983198

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}

const int MAX_N = 110100;
int par[MAX_N]; // 親
int rank_[MAX_N]; // 木の深さ
int cnt_[MAX_N]; // 属する頂点の個数(親のみ正しい)

// n要素で初期化
void UFinit(){
    for(int i=0;i<MAX_N;i++){
        par[i] = i;
        rank_[i] = 0;
        cnt_[i] = 1;
    }
}

// 木の根を求める
int find(int x){
    if(par[x] == x){
        return x;
    }else{
        return par[x] = find(par[x]);
    }
}

// xとyの属する集合を併合
void unite(int x, int y){
    x = find(x);
    y = find(y);
    if(x == y) return;

    if(rank_[x] < rank_[y]){
        par[x] = y;
        cnt_[y] += cnt_[x];
    }else{
        par[y] = x;
        cnt_[x] += cnt_[y];
        if(rank_[x] == rank_[y]) rank_[x]++;
    }
}

// xとyが同じ集合に属するか否か
bool same(int x, int y){
    return find(x) == find(y);
}


int main() {
    UFinit();
    int n,m;
    cin >> n >> m;
    int a[m], b[m];
    rep(i,m){
        cin >> a[i] >> b[i];
        a[i]--; b[i]--;
    }
    int q;
    cin >> q;
    int x[q], y[q];
    rep(i,q){
        cin >> x[i] >> y[i];
        x[i]--; y[i]--;
    }
    int l[q], r[q];
    rep(i,q){
        l[i] = 0;
        r[i] = m;
    }

    // -1判定
    rep(i,m){
        unite(a[i],b[i]);
    }
    rep(i,q){
        if(same(x[i],y[i]) == 0) l[i] = m;
    }

    rep(_,50){
        UFinit();
        vector<int> mid[m+10];
        rep(i,q) mid[(l[i]+r[i])/2].push_back(i);

        rep(i,m){
            unite(a[i],b[i]);
            rep(j,mid[i].size()){
                if(same(x[mid[i][j]], y[mid[i][j]])){
                    r[mid[i][j]] = i;
                }else{
                    l[mid[i][j]] = i;
                }
            }
        }
    }

    rep(i,q){
        int ans = -1;
        if(l[i] != m) ans = r[i]+1;
        cout << ans << endl; 
    }
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:2:35: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    2 | #define rep(i,n) for(int i = 0; i < (n); ++i)
      |                                   ^
./Main.cpp:92:13: note: in expansion of macro ‘rep’
   92 |             rep(j,mid[i].size()){
      |             ^~~

Judge Result