Submission #1256224

#	Time	Username	Problem	Language	Result	Execution time	Memory
1256224		biank	The Big Prize (IOI17_prize)	C++20	100 / 100	14 ms	916 KiB

prize

#include <bits/stdc++.h>

using namespace std;

#define forn(i, n) for (int i = 0; i < int(n); i++)
#define forsn(i, s, n) for (int i = int(s); i < int(n); i++)
#define dforn(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define dforsn(i, s, n) for (int i = int(n) - 1; i >= int(s); i--)

#define all(x) begin(x), end(x)
#define sz(x) (int)(x.size())

using vi = vector<int>;
using ll = long long;

#define pb push_back
#define eb emplace_back

#define fst first
#define snd second

vi ask(int i);

map<int, vi> memo;
bool found = false;
int maxi;

vi query(int i) {
    if (found) return {maxi, maxi};
    if (memo.count(i)) return memo[i];
    return memo[i] = ask(i);
}

int querySum(int i) {
    vi a = query(i);
    if (a[0] + a[1] == 0) found = true;
    return a[0] + a[1];
}

const int K = 450;

void solve(int lo, int hi, int s, int e) {
    if (s == e || found) return;
    if (lo == hi) {
        query(lo);
        return;
    }
    int mid = (lo + hi) / 2;
    while (!found && mid >= lo && querySum(mid) < maxi) mid--;
    if (mid >= lo) {
        solve(lo, mid, s, query(mid)[0]);
        solve((lo + hi) / 2 + 1, hi, query(mid)[0] + (lo + hi) / 2 - mid, e);
    } else {
        solve((lo + hi) / 2 + 1, hi, s + mid - lo + 1, e);
    }
}

int find_best(int n) {
    maxi = 0;
    forn(i, min(K, n)) {
        maxi = max(maxi, querySum(i));
        if ((maxi * maxi + 1LL) * (maxi * maxi + 1LL) + 1LL > n) break;
        if (found) break;
    }
    int lo = 0, hi = n - 1;
    while (!found && querySum(lo) != maxi) lo++;
    while (!found && querySum(hi) != maxi) hi--;
    solve(lo, hi, query(lo)[0], query(hi)[0]);
    for (auto [i, a] : memo) {
        if (a[0] + a[1] == 0) return i;
    }
    assert(false);
}

• Subtask 1: 20 / 20
• Subtask 2: 80 / 80