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Submission #173517

# Submission time Handle Problem Language Result Execution time Memory
173517 2020-01-04T11:27:31 Z Ruxandra985 Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 50 ms 23004 KB 
#include <cstdio>
#include <iostream>
#define MOD 1000000007
#define DIMN 2010
using namespace std;
long long dp[DIMN][DIMN] , fact[DIMN];
int main()
{
    FILE *fin = stdin;
    FILE *fout = stdout;
    long long n , cs , cf , i , j , nr;
    fscanf (fin,"%lld%lld%lld",&n,&cs,&cf);

    if (cs > cf)
        swap(cs,cf);

    dp[0][0] = 1;
    fact[0] = 1;
    for (i=1;i<=n;i++){
        fact[i] = (fact[i-1] * i)%MOD;
        if (i == cs || i == cf){ /// pe i il poti adauga doar intr o pozitie
            if (i == cs){
                for (j = 1 ; j <= i ; j ++)
                    dp[i][j] = (dp[i-1][j-1] + dp[i-1][j] * j)%MOD;
            }
            else {
                dp[i][1] = dp[i-1][1];
                for (j = 2 ; j <= i ; j ++)
                    dp[i][j] = (dp[i-1][j-1] + dp[i-1][j] * (j - 1))%MOD;
                /// ai grija sa nu pui in lantul care incepe cu cs
            }
        }
        else {
            for (j = 1 ; j <= i ; j ++){

                if (i < cf && i > cs) /// exista UN lant care incepe cu cs, pe ala nu trb sa il cuplam
                    nr = (j + (j * (j-1))%MOD)%MOD;
                else if (i > cf){
                    /// exista UN lant care se termina cu cf
                    /// si unul care INCEPE cu cs
                    nr = (2 * (j-1) + ( (j - 1) * (j - 2))%MOD )%MOD;
                    if (i == n && j == 1) /// e momentul sa le unesti pe cs si cf
                        nr = 1;
                }
                else nr = ( j * (j+1) )%MOD;

                nr = (nr + MOD) % MOD;
                dp[i][j] = ( dp[i][j] + ( dp[i-1][j+1] * nr )%MOD  )%MOD;
                if (i <= cf || j != 2)
                    dp[i][j] = ( dp[i][j] + dp[i-1][j-1] )%MOD; /// pui i singur
                /// i > cf si j = 1 presupune ca ai un lant cu cs la inc si cf la final
                /// si nu mai ai cum sa adaugi i separat ca nu poti sa dai merge dupa
            }
        }

    }
    fprintf (fout,"%lld",dp[n][1]);
    return 0;
}

Compilation message

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:12:12: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fscanf (fin,"%lld%lld%lld",&n,&cs,&cf);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 504 KB Output is correct
4 Correct 2 ms 476 KB Output is correct
5 Correct 2 ms 504 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 508 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 504 KB Output is correct
10 Correct 2 ms 504 KB Output is correct
11 Correct 2 ms 504 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 504 KB Output is correct
4 Correct 2 ms 476 KB Output is correct
5 Correct 2 ms 504 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 508 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 504 KB Output is correct
10 Correct 2 ms 504 KB Output is correct
11 Correct 2 ms 504 KB Output is correct
12 Correct 3 ms 1272 KB Output is correct
13 Correct 3 ms 1276 KB Output is correct
14 Correct 3 ms 1272 KB Output is correct
15 Correct 3 ms 1276 KB Output is correct
16 Correct 3 ms 1272 KB Output is correct
17 Correct 3 ms 1272 KB Output is correct
18 Correct 3 ms 1148 KB Output is correct
19 Correct 3 ms 1272 KB Output is correct
20 Correct 3 ms 1272 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 504 KB Output is correct
4 Correct 2 ms 476 KB Output is correct
5 Correct 2 ms 504 KB Output is correct
6 Correct 2 ms 504 KB Output is correct
7 Correct 2 ms 508 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 504 KB Output is correct
10 Correct 2 ms 504 KB Output is correct
11 Correct 2 ms 504 KB Output is correct
12 Correct 3 ms 1272 KB Output is correct
13 Correct 3 ms 1276 KB Output is correct
14 Correct 3 ms 1272 KB Output is correct
15 Correct 3 ms 1276 KB Output is correct
16 Correct 3 ms 1272 KB Output is correct
17 Correct 3 ms 1272 KB Output is correct
18 Correct 3 ms 1148 KB Output is correct
19 Correct 3 ms 1272 KB Output is correct
20 Correct 3 ms 1272 KB Output is correct
21 Correct 9 ms 4600 KB Output is correct
22 Correct 10 ms 5112 KB Output is correct
23 Correct 11 ms 5624 KB Output is correct
24 Correct 50 ms 23004 KB Output is correct
25 Correct 50 ms 23004 KB Output is correct
26 Correct 50 ms 23004 KB Output is correct
27 Correct 50 ms 22904 KB Output is correct
28 Correct 32 ms 15224 KB Output is correct