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Submission #290312

# Submission time Handle Problem Language Result Execution time Memory
290312 2020-09-03T15:46:51 Z Hehehe Calvinball championship (CEOI15_teams) C++14
20 / 100
 439 ms 716 KB 
#include<bits/stdc++.h> //:3
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define pi pair<int, int>
#define sz(x) (int)((x).size())
#define int long long

const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};

const ll inf = 2e9;
const ll mod = 1e9 + 7;
const int N = 2e4 + 11;
const int X = 1e6;
const ll INF64 = 3e18 + 1;
const double eps = 1e-14;
const double PI = acos(-1);

//ifstream in(".in");
//ofstream out(".out");

int n, a[N], dp[2][N], mx[N];

void solve(){

    cin >> n;

    for(int i = 1; i <= n; i++){
        cin >> a[i];
        mx[i] = max(mx[i - 1], a[i]);
    }

    //dp[i][j] - ways of choosing i more elements having j as the maximum element in our subsequence

    for(int i = 0; i <= n; i++){
        dp[0][i] = 1; //one way of adding 0 elements
    }

    int ans = a[n], t = 1;

    for(int i = 1; i < n; i++){//from the end to the start

        for(int j = 1; j <= n; j++){
            dp[t][j] = (dp[1 - t][j + 1] + dp[1 - t][j]*j % mod + mod) % mod;
        }

        //dp[t][j] == dp[i][j]
        //dp[1 - t][j] == dp[i - 1][j]

        ans = (ans + dp[t][mx[n - i - 1]] * (a[n - i] - 1) % mod + mod) % mod;

        t = 1 - t;

    }

    cout << (ans + mod) % mod << '\n';
}

int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);

    //cout << setprecision(6) << fixed;

    int T = 1;
    //cin >> T;
    while(T--){
        solve();
    }
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 416 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 405 ms 716 KB Output isn't correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 109 ms 632 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 439 ms 640 KB Output isn't correct
2 Halted 0 ms 0 KB -