Submission #3454907

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Source Code Expand

#include <algorithm>
#include <cstring>
#include <deque>
#include <fstream>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <vector>
using namespace std;
using ll = long long;
#define fst first
#define snd second

/* clang-format off */
template <class T, size_t D> struct _vec { using type = vector<typename _vec<T, D - 1>::type>; };
template <class T> struct _vec<T, 0> { using type = T; };
template <class T, size_t D> using vec = typename _vec<T, D>::type;
template <class T> vector<T> make_v(size_t size, const T& init) { return vector<T>(size, init); }
template <class... Ts> auto make_v(size_t size, Ts... rest) { return vector<decltype(make_v(rest...))>(size, make_v(rest...)); }
/* clang-format on */

int main() {
  int N, M;
  while (cin >> N >> M) {
    vector<int> s(M), t(M);
    for (int i = 0; i < M; i++) cin >> s[i] >> t[i], --s[i], --t[i];
    vector<int> imos(N + 1, 0);
    for (int i = 0; i < M; i++) {
      ++imos[s[i]];
      --imos[t[i] + 1];
    }
    for (int i = 1; i < N; i++) imos[i] += imos[i - 1];
    vector<int> ones(N + 1, 0);
    for (int i = 0; i < N; i++) ones[i + 1] = ones[i] + (imos[i] == 1);
    vector<int> res;
    for (int i = 0; i < M; i++) {
      if (ones[t[i] + 1] - ones[s[i]] == 0) {
        res.push_back(i);
      }
    }
    cout << res.size() << endl;
    for (int x : res) cout << x + 1 << endl;
  }
  return 0;
}

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