Submission #1048237

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048237		becaido	The Big Prize (IOI17_prize)	C++17	97.41 / 100	33 ms	2148 KiB

prize

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifdef WAIMAI
#include "grader.cpp"
#else
#include "prize.h"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

const int SIZE = 2e5 + 5;
const int K = 500;

int ans, bL, bR, mx, L[SIZE], R[SIZE];
vector<int> id;

pair<int, int> que(int i) {
    if (L[i] == -1) {
        auto v = ask(i);
        L[i] = v[0], R[i] = v[1];
    }
    return {L[i], R[i]};
}

void check(int i) {
    if (ans != -1) return;
    auto [l, r] = que(i);
    if (l + r == 0) {
        ans = i;
        return;
    }
    id.pb(i);
}
queue<tuple<int, int, int, int, int>> q;
void bfs() {
    auto [l, r, lc, rc, tot] = q.front();
    q.pop();
    if (r < bL || l > bR || ans != -1 || l > r || tot == 0) return;
    if (l == r) {
        check(l);
        return;
    }
    int mid = (l + r) / 2;
    FOR (i, mid, r) {
        if (ans != -1) return;
        auto [lcnt, rcnt] = que(i);
        if (lcnt + rcnt != mx) {
            check(i);
            if (lcnt + rcnt == 1) {
                if (lcnt == 1) bR = i;
                else bL = i;
            }
            continue;
        }
        lcnt -= lc, rcnt -= rc;
        q.emplace(l, mid - 1, lc, rc + (i - mid) + rcnt, tot - (i - mid) - rcnt);
        q.emplace(i + 1, r, lc + lcnt, rc, tot - lcnt);
        return;
    }
    q.emplace(l, mid - 1, lc, rc + (r - mid + 1), tot - (r - mid + 1));
}

int find_best(int n) {
    FOR (i, 0, n - 1) L[i] = R[i] = -1;
    if (n < K) {
        FOR (i, 0, n - 1) {
            auto [l, r] = que(i);
            if (l == 0 && r == 0) return i;
        }
    }

    mx = 0;
    FOR (i, 0, K - 1) {
        auto [l, r] = que(i);
        mx = max(mx, l + r);
    }

    id.clear();
    ans = -1;
    FOR (i, 0, K - 1) {
        auto [l, r] = que(i);
        if (l + r != mx) check(i);
    }
    bL = -1, bR = n;
    q.emplace(K, n - 1, id.size(), 0, mx - id.size());
    while (q.size()) bfs();
    for (int i : id) check(i);
    return ans;
}

/*
in1
8
3 2 3 1 3 3 2 3
*/

• Subtask 1: 20 / 20
• Subtask 2: 77.41 / 80