oj.uz

Submission #492881

# Submission time Handle Problem Language Result Execution time Memory
492881 2021-12-09T13:30:39 Z czhang2718 Kangaroo (CEOI16_kangaroo) C++17
100 / 100
 12 ms 332 KB 
#include "bits/stdc++.h"
using namespace std;

const int MOD=1e9+7;
int n, s, e;
int dp[2001], dp2[2001];

int mult(int a, int b){
  return ((long long )a*b)%MOD;
}

int add(int &a, int b){
  a+=b;
  if(a>=MOD) a-=MOD;
  return a;
}

int main(){
  cin.tie(0)->sync_with_stdio(0);
  // freopen("kangaroo.in", "r", stdin);
  // freopen("kangaroo.out", "w", stdout);

  cin >> n >> s >> e;

  dp[0]=1;
  for(int i=1; i<=n; i++){
    for(int j=0; j<i; j++){
      if(!dp[j]) continue;
      if(i==s || i==e){
        add(dp2[j+1], dp[j]);
        if(j) add(dp2[j], dp[j]);
        continue;
      }
      add(dp2[j+1], mult(dp[j], j+1-(i>s)-(i>e)));
      if(j>=2) add(dp2[j-1], mult(dp[j], j-1));
    }
    for(int j=0; j<=i; j++){
      dp[j]=dp2[j];
      dp2[j]=0;
    }
  }
  cout << dp[1];
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 204 KB Output is correct
4 Correct 0 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 0 ms 312 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 316 KB Output is correct
11 Correct 0 ms 204 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 204 KB Output is correct
4 Correct 0 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 0 ms 312 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 316 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
12 Correct 1 ms 204 KB Output is correct
13 Correct 1 ms 204 KB Output is correct
14 Correct 1 ms 204 KB Output is correct
15 Correct 1 ms 204 KB Output is correct
16 Correct 1 ms 204 KB Output is correct
17 Correct 1 ms 316 KB Output is correct
18 Correct 1 ms 204 KB Output is correct
19 Correct 1 ms 204 KB Output is correct
20 Correct 1 ms 312 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 204 KB Output is correct
4 Correct 0 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 0 ms 312 KB Output is correct
7 Correct 1 ms 204 KB Output is correct
8 Correct 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 316 KB Output is correct
11 Correct 0 ms 204 KB Output is correct
12 Correct 1 ms 204 KB Output is correct
13 Correct 1 ms 204 KB Output is correct
14 Correct 1 ms 204 KB Output is correct
15 Correct 1 ms 204 KB Output is correct
16 Correct 1 ms 204 KB Output is correct
17 Correct 1 ms 316 KB Output is correct
18 Correct 1 ms 204 KB Output is correct
19 Correct 1 ms 204 KB Output is correct
20 Correct 1 ms 312 KB Output is correct
21 Correct 2 ms 332 KB Output is correct
22 Correct 2 ms 332 KB Output is correct
23 Correct 2 ms 204 KB Output is correct
24 Correct 11 ms 328 KB Output is correct
25 Correct 10 ms 312 KB Output is correct
26 Correct 12 ms 312 KB Output is correct
27 Correct 12 ms 204 KB Output is correct
28 Correct 6 ms 204 KB Output is correct