Submission #620486

#	Time	Username	Problem	Language	Result	Execution time	Memory
620486		Genius3435	Gondola (IOI14_gondola)	C++17	100 / 100	71 ms	5912 KiB

gondola

#include <bits/stdc++.h>
using namespace std;

#include "gondola.h"
 
constexpr int N = 100005;
constexpr int M = 250005;
constexpr int MOD = 1000000009;
 
int valid(int n, int a[]) {
    // Check that values \leq n are in order, and that there are no repeats
 
    set<int> contained;
    for (int i = 0; i < n; ++i) {
        if (contained.count(a[i])) return 0;
        contained.insert(a[i]);
    }
 
 
    int start_index = -1;
    for (int i = 0; i < n; ++i) {
        if (a[i] <= n) {
            int index = (a[i] - (i+1) + n) % n;
            if (start_index == -1) {
                start_index = index;
            } else if (start_index != index) {
                return 0;
            }
        }
    }
 
    return 1;
}
 
 
 
int replacement(int n, int a[], int b[]) {
    static int position[M];
    auto it = max_element(a, a+n);
    int m = *it, max_idx = it-a;
    for (int i = 1; i <= m; ++i) {
        position[i] = -1;
    }
    for (int i = 0; i < n; ++i) {
        position[a[i]] = i;
    }
 
 
    int start_index = -1;
    for (int i = 0; i < n; ++i) {
        if (a[i] <= n) {
            start_index = (a[i] - (i+1) + n) % n;
            break;
        }
    }
    if (start_index == -1) {
        start_index = 0;
    }
 
 
    int *currSeq = new int[n];
    for (int i = 0; i < n; ++i) {
        currSeq[i] = (start_index + i) % n + 1;
    }
 
    for (int i = n+1; i <= m; ++i) {
        if (position[i] == -1) {
            b[i-n-1] = currSeq[max_idx];
            currSeq[max_idx] = i;
        } else {
            b[i-n-1] = currSeq[position[i]];
            currSeq[position[i]] = i;
        }
    }
 
    delete[] currSeq;
 
    return m-n;
}
 
 
 
int pow(long long b, int e, int m) {
    long long p = 1;
    while (e) {
        if (e&1) p = p * b % m;
        e >>= 1, b = b * b % m;
    }
    return p;
}
 
int countReplacement(int n, int a[]) {
    if (!valid(n, a)) return 0;
 
    std::set<int> contained;
    for (int i = 0; i < n; ++i) {
        if (a[i] > n) {
            contained.insert(a[i]);
        }
    }
 
    int positions = contained.size();
    long long ans = positions<n ? 1 : n;
    int prv = n;
    for (const int i : contained) {
        // All values in the interval (prv, i) have positions spots they could go in
        ans = ans * pow(positions, i-prv-1, MOD) % MOD;
        prv = i;
        positions--;
    }
    return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 10 / 10
• Subtask 4: 5 / 5
• Subtask 5: 10 / 10
• Subtask 6: 20 / 20
• Subtask 7: 5 / 5
• Subtask 8: 15 / 15
• Subtask 9: 15 / 15
• Subtask 10: 10 / 10