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답안 #443099

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
443099 2021-07-09T16:18:01 Z tranxuanbach 캥거루 (CEOI16_kangaroo) C++17
100 / 100
 38 ms 15940 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define endl '\n'
#define fi first
#define se second
#define For(i, l, r) for (int i = l; i < r; i++)
#define ForE(i, l, r) for (int i = l; i <= r; i++)
#define FordE(i, l, r) for (int i = l; i >= r; i--)
#define Fora(v, a) for (auto v: a)
#define bend(a) a.begin(), a.end()
#define isz(a) ((signed)a.size())

using ll = long long;
using ld = long double;
using pii = pair <int, int>;
using vi = vector <int>;
using vpii = vector <pii>;
using vvi = vector <vi>;

const int maxN = 2e3 + 5, mod = 1e9 + 7;

void sadd(int& x, int y){
    if ((x += y) >= mod) x -= mod; return;
}

int add(int x, int y){
    if ((x += y) >= mod) x -= mod; return x;
}

void ssub(int& x, int y){
    if ((x -= y) < 0) x += mod; return;
}

int sub(int x, int y){
    if ((x -= y) < 0) x += mod; return x;
}

int mul(int x, int y){
    return 1ll * x * y % mod;
}

int binpow(int x, int y){
    int ans = 1;
    while (y){
        if (y & 1) ans = mul(ans, x);
        x = mul(x, x);
        y >>= 1;
    }
    return ans;
}

int inv(int x){
    return binpow(x, mod - 2);
}

#define div __div__
int div(int x, int y){
    return mul(x, binpow(y, mod - 2));
}

int n, cs, cf;
int dp[maxN][maxN];

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    // freopen("KEK.inp", "r", stdin);
    // freopen("KEK.out", "w", stdout);
    cin >> n >> cs >> cf;
    dp[0][0] = 1;
    int cap = 0;
    ForE(i, 1, n){
        ForE(cc, 1, n){
            if (i == cs or i == cf){
                sadd(dp[i][cc], dp[i - 1][cc - 1]);
                sadd(dp[i][cc], dp[i - 1][cc]);
                continue;
            }
            sadd(dp[i][cc], mul(dp[i - 1][cc - 1], cc - cap));
            sadd(dp[i][cc], mul(dp[i - 1][cc + 1], cc));
        }
        if (i == cs or i == cf){
            cap++;
        }
    }
    cout << dp[n][1] << endl;
}

/*
==================================================+
INPUT:                                            |
--------------------------------------------------|

--------------------------------------------------|
==================================================+
OUTPUT:                                           |
--------------------------------------------------|

--------------------------------------------------|
==================================================+
*/

Compilation message

kangaroo.cpp: In function 'void sadd(int&, int)':
kangaroo.cpp:27:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   27 |     if ((x += y) >= mod) x -= mod; return;
      |     ^~
kangaroo.cpp:27:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   27 |     if ((x += y) >= mod) x -= mod; return;
      |                                    ^~~~~~
kangaroo.cpp: In function 'int add(int, int)':
kangaroo.cpp:31:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   31 |     if ((x += y) >= mod) x -= mod; return x;
      |     ^~
kangaroo.cpp:31:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   31 |     if ((x += y) >= mod) x -= mod; return x;
      |                                    ^~~~~~
kangaroo.cpp: In function 'void ssub(int&, int)':
kangaroo.cpp:35:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   35 |     if ((x -= y) < 0) x += mod; return;
      |     ^~
kangaroo.cpp:35:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   35 |     if ((x -= y) < 0) x += mod; return;
      |                                 ^~~~~~
kangaroo.cpp: In function 'int sub(int, int)':
kangaroo.cpp:39:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   39 |     if ((x -= y) < 0) x += mod; return x;
      |     ^~
kangaroo.cpp:39:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   39 |     if ((x -= y) < 0) x += mod; return x;
      |                                 ^~~~~~

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct

Subtask #3
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1088 KB Output is correct
14 Correct 2 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1228 KB Output is correct
17 Correct 1 ms 1228 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 2 ms 1224 KB Output is correct
20 Correct 1 ms 1228 KB Output is correct

Subtask #4
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 460 KB Output is correct
12 Correct 1 ms 1228 KB Output is correct
13 Correct 1 ms 1088 KB Output is correct
14 Correct 2 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1228 KB Output is correct
17 Correct 1 ms 1228 KB Output is correct
18 Correct 1 ms 1100 KB Output is correct
19 Correct 2 ms 1224 KB Output is correct
20 Correct 1 ms 1228 KB Output is correct
21 Correct 6 ms 4556 KB Output is correct
22 Correct 7 ms 4940 KB Output is correct
23 Correct 7 ms 5452 KB Output is correct
24 Correct 34 ms 15888 KB Output is correct
25 Correct 35 ms 15912 KB Output is correct
26 Correct 38 ms 15908 KB Output is correct
27 Correct 33 ms 15940 KB Output is correct
28 Correct 27 ms 11976 KB Output is correct