Submission #118382

#	Time	Username	Problem	Language	Result	Execution time	Memory
118382		silxikys	Calvinball championship (CEOI15_teams)	C++14	10 / 100	19 ms	8576 KiB

teams

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

const int maxn = 1e4+4, M = 1e9+7;
int n, a[maxn];

void madd(int& a, int b) {
    a = (a+b) % M;
}

/*
 * f(i,j) = # combinations, w/ i spaces left, that can be up to j
 * f(i,j) = j*f(i-1,j) + f(i-1,j+1)
 * f(0,x) = 1
 * f(1,x) = x
 * f(2,x) = j*x+x+1 = (j+1)*x+1
 *
 * */

int dp[1003][1003];

int main()
{
    //ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    
    for (int i = 0; i < 1003; i++) {
        dp[1][i] = i;
    }
    int sum = 0;
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= n-i; j++) {
            dp[i][j] = (j-1)*dp[i-1][j] + dp[i-1][j+1];
            //printf("[%d][%d]: %d\n",i,j,dp[i][j]);
            //cout << dp[i][j] << ' ';
            //madd(sum,dp[i][j]);
        }
        /*
        cout << '\n';
        cout << i << ": " << sum << '\n';
        */
    }
    int ans = 0;
    for (int i = 1; i <= n; i++) {
        madd(ans,dp[n+1-i][a[i]-1]);
    }
    madd(ans,1);
    cout << ans << '\n';
}

Compilation message (stderr)

teams.cpp: In function 'int main()':
teams.cpp:34:9: warning: unused variable 'sum' [-Wunused-variable]
     int sum = 0;
         ^~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10