Submission #374846

#	Time	Username	Problem	Language	Result	Execution time	Memory
374846		valerikk	Xylophone (JOI18_xylophone)	C++17	100 / 100	130 ms	620 KiB

xylophone

/*
    doing virtual contest
    start: 10:00
    finish: 14:00
*/
#include <bits/stdc++.h>

using namespace std;

int query(int s, int t);
void answer(int i, int a);

#ifndef EVAL
const int N_ = 5007;

int n_;
int a_[N_], ans_[N_];

int query(int s, int t) {
    int mn = n_, mx = 1;
    for (int i = s; i <= t; ++i) {
        mn = min(mn, a_[i]);
        mx = max(mx, a_[i]);
    }
    return mx - mn;
}

void answer(int i, int a) {
    if (i < 1 || i > n_) {
        cout << "incorrect index " << i << endl;
        exit(0);
    }
    if (ans_[i] != -1) {
        cout << i << " used twice" << endl;
        exit(0);
    }
    ans_[i] = a;
}

void check_ans() {
    bool corr = 1;
    for (int i = 1; i <= n_; ++i) corr &= a_[i] == ans_[i];
    if (!corr) {
        cout << "incorrect" << endl;
        for (int i = 1; i <= n_; ++i) cout << a_[i] << " ";
        cout << endl;
        for (int i = 1; i <= n_; ++i) cout << ans_[i] << " ";
        cout << endl;
    } else {
        cout << "correct\n";
    }
}

void init(int n, vector<int> a) {
    n_ = n;
    for (int i = 1; i <= n; ++i) {
        a_[i] = a[i - 1];
        ans_[i] = -1;
    }
}
#endif

void solve(int n) {
    vector<int> a(n + 1, -1);
    a[1] = 0;
    if (2 <= n) a[2] = query(1, 2);
    for (int i = 3; i <= n; ++i) {
        int x = a[i - 2], y = a[i - 1];
        int d = query(i - 1, i);
        if (abs(x - y) + d == query(i - 2, i)) {
            a[i] = y < x ? y - d : y + d;
        } else {
            a[i] = y < x ? y + d : y - d;
        }
    }
    int mn = (int)1e9;
    for (int i = 1; i <= n; ++i) mn = min(mn, a[i]);
    for (int i = 1; i <= n; ++i) a[i] += -mn + 1;
    int pos1 = -1, posn = -1;
    for (int i = 1; i <= n; ++i) {
        if (a[i] == 1) pos1 = i;
        if (a[i] == n) posn = i;
    }
    if (pos1 > posn) {
        for (int i = 1; i <= n; ++i) a[i] = n - a[i] + 1;
    }
    for (int i = 1; i <= n; ++i) answer(i, a[i]);
}

#ifndef EVAL
int main() {
    freopen("input.txt", "r", stdin);
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) cin >> a[i];
    init(n, a);
    solve(n);
    check_ans();
    return 0;
}
#endif

• Subtask 1: 11 / 11
• Subtask 2: 36 / 36
• Subtask 3: 53 / 53