oj.uz

Submission #242980

# Submission time Handle Problem Language Result Execution time Memory
242980 2020-06-30T03:52:18 Z abacaba Kangaroo (CEOI16_kangaroo) C++14
100 / 100
 58 ms 16256 KB 
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <chrono>
#include <vector>
#include <map>
#include <random>
#include <set>
#include <algorithm>
#include <math.h>
#include <stdio.h>
#include <queue>
#include <bitset>
#include <deque>
#include <cassert>
using namespace std;

const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;
const int N = 2e3 + 15;
int n, s, t, dp[N][N];

inline int add(int a, int b) {
    a += b;
    if(a >= mod)
        a -= mod;
    else if(a < 0)
        a += mod;
    return a;
}

inline void add_t(int &a, int b) {
    a = add(a, b);
}

inline int mt(int a, int b) {
    return 1ll * a * b % mod;
}

main() {
    ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
    // freopen("input.txt", "r", stdin);
    cin >> n >> s >> t;
    if(s > t)
        swap(s, t);
    dp[1][1] = 1;
    for(int i = 2; i <= n; ++i) {
        for(int j = 1; j <= n; ++j) {
            if(i == s || i == t)
                add_t(dp[i][j], add(dp[i-1][j-1], dp[i-1][j]));
            else
                add_t(dp[i][j], add(mt(dp[i-1][j+1], j), mt(dp[i-1][j-1], j - (i > s) - (i > t))));
        }
    }
    cout << dp[n][1] << endl;
    return 0;
}

Compilation message

kangaroo.cpp:41:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 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 512 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 4 ms 384 KB Output is correct
2 Correct 4 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 512 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 1280 KB Output is correct
13 Correct 5 ms 1280 KB Output is correct
14 Correct 6 ms 1408 KB Output is correct
15 Correct 6 ms 1280 KB Output is correct
16 Correct 5 ms 1280 KB Output is correct
17 Correct 6 ms 1280 KB Output is correct
18 Correct 5 ms 1152 KB Output is correct
19 Correct 6 ms 1280 KB Output is correct
20 Correct 6 ms 1280 KB Output is correct

Subtask #4
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 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 512 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 1280 KB Output is correct
13 Correct 5 ms 1280 KB Output is correct
14 Correct 6 ms 1408 KB Output is correct
15 Correct 6 ms 1280 KB Output is correct
16 Correct 5 ms 1280 KB Output is correct
17 Correct 6 ms 1280 KB Output is correct
18 Correct 5 ms 1152 KB Output is correct
19 Correct 6 ms 1280 KB Output is correct
20 Correct 6 ms 1280 KB Output is correct
21 Correct 12 ms 4736 KB Output is correct
22 Correct 12 ms 5120 KB Output is correct
23 Correct 13 ms 5632 KB Output is correct
24 Correct 50 ms 16256 KB Output is correct
25 Correct 48 ms 16120 KB Output is correct
26 Correct 58 ms 16100 KB Output is correct
27 Correct 48 ms 16120 KB Output is correct
28 Correct 31 ms 12280 KB Output is correct