제출 #251137

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
251137		Sorting	Calvinball championship (CEOI15_teams)	C++14	100 / 100	556 ms	780 KiB

teams

#include <bits/stdc++.h>

using namespace std;

const int k_N = 1e4 + 3;
const long long k_Mod = 1e6 + 7;

int n, a[k_N];
long long dp[2][k_N][2];

long long solve(int pos, int cnt, bool equal){
    if(pos == n) return 1;
    return dp[pos & 1][cnt][equal];
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n;
    for(int i = 0; i < n; ++i)
        cin >> a[i];

    for(int pos = n - 1; pos >= 0; --pos){
        for(int cnt = 0; cnt <= pos; ++cnt){
            for(short equal = 0; equal <= 1; ++equal){
                auto &ans = dp[pos & 1][cnt][equal];
                ans = 0;

                if(!equal){ 
                    ans = (solve(pos + 1, cnt, false) * cnt + solve(pos + 1, cnt + 1, false)) % k_Mod;
                    continue;
                }

                ans = solve(pos + 1, cnt, false) * min(cnt, a[pos] - 1) % k_Mod;
                if(a[pos] <= cnt)          ans += solve(pos + 1, cnt, true);
                else if(a[pos] == cnt + 1) ans += solve(pos + 1, cnt + 1, true);
                else if(a[pos] > cnt + 1)  ans += solve(pos + 1, cnt + 1, false);
                ans %= k_Mod;
            }
        }
    }

    cout << solve(0, 0, true) << "\n";
}

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