oj.uz

Submission #231774

# Submission time Handle Problem Language Result Execution time Memory
231774 2020-05-14T17:26:42 Z nicolaalexandra Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 38 ms 14200 KB 
#include <bits/stdc++.h>
#define DIM 2010
#define MOD 1000000007
using namespace std;
int dp[DIM][DIM];
int n,i,j,k,t,st,fn;
int _(int x){
    while (x < 0)
        x += MOD;
    while (x >= MOD)
        x -= MOD;
    return x;
}
int main (){

    //ifstream cin ("kangaroo.in");
   // ofstream cout ("kangaroo.out");

    cin>>n>>st>>fn;
    /// dp[i][j]
    /// la un pas pot sa creez un grup nou sau sa unesc doua grupuri
    dp[0][0] = 1, k = 0;
    for (i=1;i<=n;i++){
        if (i == st || i == fn)
            k++;
        for (j=1;j<=i;j++){
            if (i == st || i == fn){
                dp[i][j] = _(dp[i-1][j-1] + dp[i-1][j]);
            } else {
                /// creez grup nou
                int cnt = j - k;
                dp[i][j] = _(dp[i][j] + 1LL*cnt*dp[i-1][j-1]%MOD);
                /// unesc doua grupuri
                dp[i][j] = _(dp[i][j] + 1LL*j*dp[i-1][j+1]%MOD);
            }}}

    cout<<dp[n][1];

    /*
    /// dp[i][j][k][0/1] - nr de permutari de lg i care incep pe j si se termina pe k si sa inceapa crescator / descrescator
    dp[2][1][2][0] = dp[2][2][1][1] = 1;

    for (i=3;i<=n;i++){
        for (j=1;j<=i;j++){
            for (k=j+1;k<=i;k++){

                if (j == 1){
                    for (t=2;t<=i;t++)
                        dp[i][j][k][0] = _(dp[i][j][k][0] + dp[i-1][t][k-1][1]);
                } else dp[i][j][k][0] = _(dp[i][j-1][k][0] - dp[i-1][j-1][k-1][1]);


                dp[i][j][k][1] = _(dp[i][j-1][k][1] + dp[i-1][j-1][k-1][0]);

                if (i%2)
                    dp[i][k][j][0] = dp[i][j][k][0], dp[i][k][j][1] = dp[i][j][k][1];
                else dp[i][k][j][0] = dp[i][j][k][1], dp[i][k][j][1] = dp[i][j][k][0];

            }
        }
    }

    if (st > fn)
        swap (st,fn);

    cout<<_(dp[n][st][fn][0] + dp[n][st][fn][1]);
    */

    return 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 512 KB Output is correct
4 Correct 5 ms 512 KB Output is correct
5 Correct 5 ms 416 KB Output is correct
6 Correct 5 ms 512 KB Output is correct
7 Correct 5 ms 512 KB Output is correct
8 Correct 5 ms 512 KB Output is correct
9 Correct 5 ms 512 KB Output is correct
10 Correct 5 ms 512 KB Output is correct
11 Correct 5 ms 512 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 512 KB Output is correct
4 Correct 5 ms 512 KB Output is correct
5 Correct 5 ms 416 KB Output is correct
6 Correct 5 ms 512 KB Output is correct
7 Correct 5 ms 512 KB Output is correct
8 Correct 5 ms 512 KB Output is correct
9 Correct 5 ms 512 KB Output is correct
10 Correct 5 ms 512 KB Output is correct
11 Correct 5 ms 512 KB Output is correct
12 Correct 5 ms 1152 KB Output is correct
13 Correct 5 ms 1152 KB Output is correct
14 Correct 5 ms 1152 KB Output is correct
15 Correct 5 ms 1152 KB Output is correct
16 Correct 5 ms 1152 KB Output is correct
17 Correct 5 ms 1152 KB Output is correct
18 Correct 5 ms 1152 KB Output is correct
19 Correct 5 ms 1152 KB Output is correct
20 Correct 5 ms 1152 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 512 KB Output is correct
4 Correct 5 ms 512 KB Output is correct
5 Correct 5 ms 416 KB Output is correct
6 Correct 5 ms 512 KB Output is correct
7 Correct 5 ms 512 KB Output is correct
8 Correct 5 ms 512 KB Output is correct
9 Correct 5 ms 512 KB Output is correct
10 Correct 5 ms 512 KB Output is correct
11 Correct 5 ms 512 KB Output is correct
12 Correct 5 ms 1152 KB Output is correct
13 Correct 5 ms 1152 KB Output is correct
14 Correct 5 ms 1152 KB Output is correct
15 Correct 5 ms 1152 KB Output is correct
16 Correct 5 ms 1152 KB Output is correct
17 Correct 5 ms 1152 KB Output is correct
18 Correct 5 ms 1152 KB Output is correct
19 Correct 5 ms 1152 KB Output is correct
20 Correct 5 ms 1152 KB Output is correct
21 Correct 9 ms 3840 KB Output is correct
22 Correct 11 ms 4096 KB Output is correct
23 Correct 10 ms 4480 KB Output is correct
24 Correct 38 ms 14200 KB Output is correct
25 Correct 34 ms 14200 KB Output is correct
26 Correct 35 ms 14200 KB Output is correct
27 Correct 34 ms 14080 KB Output is correct
28 Correct 23 ms 10240 KB Output is correct