Submission #390022

#	Time	Username	Problem	Language	Result	Execution time	Memory
390022		acm	Fountain (eJOI20_fountain)	C++14	100 / 100	417 ms	40824 KiB

fountain

#include <bits/stdc++.h>
#define speed                   \
  ios_base::sync_with_stdio(0); \
  cin.tie(0);                   \
  cout.tie(0);
#define precision     \
  cout.precision(30); \
  cerr.precision(10);
#define ll long long
#define ld long double
#define pll pair<ll, ll>
#define pii pair<int, int>
#define forn(n) for (int i = 1; i <= n; i++)
#define forlr(l, r) for (int i = l; i != r; (l > r ? i-- : i++))
#define pb(x) push_back(x)
#define sz(x) (int)x.size()
#define mp(x, y) make_pair(x, y)
#define all(x) x.begin(), x.end()
#define pc(x) __builtin_popcount(x)
#define pcll(x) __builtin_popcountll(x)
#define F first
#define S second
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
void ioi(string name) {
  freopen((name + ".in").c_str(), "r", stdin);
  freopen((name + ".out").c_str(), "w", stdout);
}
ll n, q, a[200005], b[200005], up[200005][21], pu[200005][21];
vector<ll> v;
int main() {
  speed;
  precision;
  // code
  cin >> n >> q;
  for (int i = 1; i <= n; i++) {
    cin >> a[i] >> b[i];
  }
  a[n + 1] = b[n + 1] = (1 << 30);
  up[n + 1][0] = n + 1;
  v.pb(n + 1);
  for (int i = n; i >= 1; i--) {
    while (a[v.back()] <= a[i]) v.pop_back();
    up[i][0] = v.back();
    pu[i][0] = b[up[i][0]];
    v.pb(i);
  }
  for (int i = 1; i <= 20; i++) {
    for (int j = 1; j <= n + 1; j++) {
      up[j][i] = up[up[j][i - 1]][i - 1];
      pu[j][i] = pu[j][i - 1] + pu[up[j][i - 1]][i - 1];
    }
  }
  while (q--) {
    ll v, r;
    cin >> v >> r;
    r -= b[v];
    for (int i = 20; i >= 0; i--) {
      if (pu[v][i] <= r) {
        r -= pu[v][i];
        v = up[v][i];
      }
    }
    if (r > 0) v = up[v][0];
    cout << (v > n ? 0 : v) << "\n";
  }
  // endl
#ifndef ONLINE_JUDGE
  cerr << "\nTime elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
  return 0;
}

Compilation message (stderr)

fountain.cpp: In function 'void ioi(std::string)':
fountain.cpp:26:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   26 |   freopen((name + ".in").c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fountain.cpp:27:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   27 |   freopen((name + ".out").c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40