Submission #537077

#	Time	Username	Problem	Language	Result	Execution time	Memory
537077		timreizin	Gondola (IOI14_gondola)	C++17	75 / 100	34 ms	4896 KiB

gondola

#include "gondola.h"
#include <vector>
#include <algorithm>
#include <set>
#include <numeric>

using namespace std;

int valid(int n, int inputSeq[])
{
    vector<int> a(n);
    int d = 0;
    for (int i = 0; i < n; ++i) if (inputSeq[i] <= n) d = (i - inputSeq[i] + 1 + n) % n;
    for (int i = 0; i < n; ++i) a[(i - d + n) % n] = inputSeq[i] - 1;
    if (set<int>(a.begin(), a.end()).size() != n) return 0;
    for (int i = 0; i < n; ++i) if (a[i] < n && a[i] != i) return 0;
    return 1;
}

//----------------------

int replacement(int n, int gondolaSeq[], int replacementSeq[])
{
    vector<int> a(n);
    int d = 0;
    for (int i = 0; i < n; ++i) if (gondolaSeq[i] <= n) d = (i - gondolaSeq[i] + 1 + n) % n;
    for (int i = 0; i < n; ++i) a[(i - d + n) % n] = gondolaSeq[i];
    vector<int> inds(n);
    iota(inds.begin(), inds.end(), 0);
    sort(inds.begin(), inds.end(), [&a](int l, int r){ return a[l] < a[r]; });
    int l = 0, next = n + 1;
    for (int i : inds)
    {
        if (a[i] < next) continue;
        replacementSeq[l++] = i + 1;
        for (; next < a[i]; ++next) replacementSeq[l++] = next;
        ++next;
    }
    return l;
}

//----------------------

using ll = long long;

const ll MOD = 1e9 + 9;

ll binPow(ll a, ll n)
{
    ll res = 1;
    while (n)
    {
        if (n & 1) res = (res * a) % MOD;
        a = (a * a) % MOD;
        n >>= 1;
    }
    return res;
}

int countReplacement(int n, int inputSeq[])
{
    if (!valid(n, inputSeq)) return 0;
    vector<int> inds(n);
    iota(inds.begin(), inds.end(), 0);
    sort(inds.begin(), inds.end(), [inputSeq](int l, int r){ return inputSeq[l] < inputSeq[r]; });
    ll last = n, counter = n;
    for (int i = 0; i < n; ++i) counter -= inputSeq[i] <= n;
    ll res = 1;
    for (int i : inds)
    {
        if (inputSeq[i] <= n) continue;
        ll d = inputSeq[i] - last;
        res = (res * binPow(counter, d - 1)) % MOD;
        last = inputSeq[i];
        --counter;
    }
    return res;
}

Compilation message (stderr)

gondola.cpp: In function 'int valid(int, int*)':
gondola.cpp:15:45: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   15 |     if (set<int>(a.begin(), a.end()).size() != n) return 0;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

• 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: 0 / 15
• Subtask 10: 0 / 10