Submission #2549228

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;

template< typename Monoid >
struct SegmentTree {
  using F = function< Monoid(Monoid, Monoid) >;
 
  int sz;
  vector< Monoid > seg;
 
  const F f;
  const Monoid M1;
 
  SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while(sz < n) sz <<= 1;
    seg.assign(2 * sz, M1);
  }
 
  void set(int k, const Monoid &x) {
    seg[k + sz] = x;
  }
 
  void build() {
    for(int k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
 
  void update(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while(k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
 
  Monoid query(int a, int b) {
    Monoid L = M1, R = M1;
    for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if(a & 1) L = f(L, seg[a++]);
      if(b & 1) R = f(seg[--b], R);
    }
    return f(L, R);
  }
 
  Monoid operator[](const int &k) const {
    return seg[k + sz];
  }
};

int N, M;
int s[300100], t[300100];
vi ans;

int f(int a, int b) {
    return min(a, b);
}

void solve() {
    cin >> N >> M;
    rep(i,M) {
        cin >> s[i] >> t[i];
        s[i]--; t[i]--;
    }
    int imos[N] = {};
    rep(i,M) {
        imos[s[i]]++;
        if (t[i] + 1 < N) imos[t[i]+1]--;
    }
    REP(i,1,N) imos[i] += imos[i-1];
    SegmentTree<int> seg(N, f, INT_MAX);
    rep(i,N) {
        seg.update(i, imos[i]);
    }
    rep(i,M) {
        int mn = seg.query(s[i], t[i]+1);
        if (mn >= 2) ans.push_back(i+1);
    }
    cout << ans.size() << endl;
    rep(i,ans.size()) cout << ans[i] << endl;
}

int main() {
    cin.tie(0);
   	ios::sync_with_stdio(false);
    solve();
    return 0;
}

Submission Info

Judge Result