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답안 #127484

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
127484 2019-07-09T12:34:39 Z RockyB Tents (JOI18_tents) C++17
100 / 100
 367 ms 35836 KB 
#include <bits/stdc++.h>

#define rep(a, b, c) for (int a = (b); (a) <= (c); a++)
#define per(a, b, c) for (int a = (b); (a) >= (c); a--)

#define nl '\n'
#define ioi exit(0);

const int mod = (int)1e9 + 7;
const int N = (int)1e4;

using namespace std;

void add(int &x, int y) {
  x += y;
  if (x >= mod) x -= mod;
  if (x < 0) x += mod;
}
int sum(int x, int y) {
  add(x, y);
  return x;
}
int n, m;

int dp[3001][3001];
int calc(int v = n, int free = m) {
  if (!v) return 1;
  if (~dp[v][free]) return dp[v][free];
  int res = calc(v - 1, free);
  // put < or > or ^ or v
  if (free > 0) {
    add(res, calc(v - 1, free - 1) * 1ll * free * 4 % mod);
    // connect v and ^
    if (v > 1) add(res, calc(v - 2, free - 1) * 1ll * (v - 1) * free % mod);
  }
  // connect > and <
  if (free > 1) add(res, calc(v - 1, free - 2) * 1ll * (free * (free - 1) / 2) % mod);
  return dp[v][free] = res;
}
int main() {
  #ifdef IOI
    freopen ("in.txt", "r", stdin);
    freopen ("slow.out", "w", stdout);
  #endif
  cin >> n >> m;
  memset(dp, -1, sizeof(dp));
  int ans = sum(calc(), -1);
  cout << ans << nl;
  ioi
}

/*

5116 0
3720 1
450 2

*/

Subtask #1
48.0 / 48.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 35576 KB Output is correct
2 Correct 31 ms 35576 KB Output is correct
3 Correct 31 ms 35576 KB Output is correct
4 Correct 37 ms 35704 KB Output is correct
5 Correct 37 ms 35576 KB Output is correct
6 Correct 38 ms 35576 KB Output is correct
7 Correct 32 ms 35576 KB Output is correct
8 Correct 37 ms 35576 KB Output is correct
9 Correct 37 ms 35576 KB Output is correct
10 Correct 39 ms 35576 KB Output is correct
11 Correct 37 ms 35576 KB Output is correct
12 Correct 34 ms 35548 KB Output is correct

Subtask #2
52.0 / 52.0

# 결과 실행 시간 메모리 Grader output
1 Correct 31 ms 35576 KB Output is correct
2 Correct 31 ms 35576 KB Output is correct
3 Correct 31 ms 35576 KB Output is correct
4 Correct 37 ms 35704 KB Output is correct
5 Correct 37 ms 35576 KB Output is correct
6 Correct 38 ms 35576 KB Output is correct
7 Correct 32 ms 35576 KB Output is correct
8 Correct 37 ms 35576 KB Output is correct
9 Correct 37 ms 35576 KB Output is correct
10 Correct 39 ms 35576 KB Output is correct
11 Correct 37 ms 35576 KB Output is correct
12 Correct 34 ms 35548 KB Output is correct
13 Correct 31 ms 35556 KB Output is correct
14 Correct 32 ms 35676 KB Output is correct
15 Correct 246 ms 35704 KB Output is correct
16 Correct 33 ms 35576 KB Output is correct
17 Correct 52 ms 35576 KB Output is correct
18 Correct 82 ms 35592 KB Output is correct
19 Correct 283 ms 35824 KB Output is correct
20 Correct 223 ms 35704 KB Output is correct
21 Correct 142 ms 35832 KB Output is correct
22 Correct 159 ms 35796 KB Output is correct
23 Correct 112 ms 35836 KB Output is correct
24 Correct 367 ms 35704 KB Output is correct
25 Correct 274 ms 35704 KB Output is correct
26 Correct 319 ms 35704 KB Output is correct
27 Correct 355 ms 35832 KB Output is correct