Submission #899056

# Submission time Handle Problem Language Result Execution time Memory
899056 2024-01-05T12:26:56 Z lovrot Tents (JOI18_tents) C++17
100 / 100
270 ms 71880 KB
#include <cstdio> 
#include <cstring> 

using namespace std;

typedef long long ll; 

const int N = 3010; 
const int MOD = 1e9 + 7;

inline int add(int a, int b) {
	if(a + b < MOD) return a + b;
	return a + b - MOD; 
}

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

inline int pot(int a, int b) {
	int ret = 1;
	for(; b; b /= 2, a = mult(a, a))
		if(b & 1) ret = mult(ret, a);
	return ret;
}

inline int inv(int a) {
	return pot(a, MOD - 2);
}

int w, h;

int C[N][N], DP[N][N];

int choose(int a, int b) {
	if(a == b|| !b) return 1;
	if(C[a][b] != -1) return C[a][b];
	return C[a][b] = add(choose(a - 1, b), choose(a - 1, b - 1));
}

int dp(int n, int m) {
	if(!n || !m) return 1;
	if(DP[n][m] != -1) return DP[n][m]; 
	
	int a = 0, b = 0, c = 0, d = 0;
	a = dp(n - 1, m); 
	b = mult(mult(4, m), dp(n - 1, m - 1)); 
	if(m > 1) c = mult(choose(m, 2), dp(n - 1, m - 2));
	if(n > 1) d = mult(mult(m, n - 1), dp(n - 2, m - 1));
//	printf("%d %d %d %d %d %d\n", n, m, a, b, c, d);
	return DP[n][m] = add(a, add(b, add(c, d)));
}

int main() {
	memset(C, -1, sizeof(C));
	memset(DP, -1, sizeof(DP));

	scanf("%d%d", &h, &w); 
	printf("%d\n", add(MOD - 1, dp(h, w)));	
	return 0;
}

Compilation message

tents.cpp: In function 'int main()':
tents.cpp:58:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |  scanf("%d%d", &h, &w);
      |  ~~~~~^~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 13 ms 71260 KB Output is correct
2 Correct 8 ms 71260 KB Output is correct
3 Correct 9 ms 71260 KB Output is correct
4 Correct 9 ms 71316 KB Output is correct
5 Correct 9 ms 71512 KB Output is correct
6 Correct 9 ms 71260 KB Output is correct
7 Correct 9 ms 71260 KB Output is correct
8 Correct 9 ms 71260 KB Output is correct
9 Correct 8 ms 71260 KB Output is correct
10 Correct 10 ms 71276 KB Output is correct
11 Correct 9 ms 71256 KB Output is correct
12 Correct 11 ms 71276 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 13 ms 71260 KB Output is correct
2 Correct 8 ms 71260 KB Output is correct
3 Correct 9 ms 71260 KB Output is correct
4 Correct 9 ms 71316 KB Output is correct
5 Correct 9 ms 71512 KB Output is correct
6 Correct 9 ms 71260 KB Output is correct
7 Correct 9 ms 71260 KB Output is correct
8 Correct 9 ms 71260 KB Output is correct
9 Correct 8 ms 71260 KB Output is correct
10 Correct 10 ms 71276 KB Output is correct
11 Correct 9 ms 71256 KB Output is correct
12 Correct 11 ms 71276 KB Output is correct
13 Correct 9 ms 71344 KB Output is correct
14 Correct 9 ms 71516 KB Output is correct
15 Correct 185 ms 71684 KB Output is correct
16 Correct 11 ms 71260 KB Output is correct
17 Correct 27 ms 71348 KB Output is correct
18 Correct 50 ms 71260 KB Output is correct
19 Correct 206 ms 71696 KB Output is correct
20 Correct 164 ms 71512 KB Output is correct
21 Correct 96 ms 71564 KB Output is correct
22 Correct 111 ms 71512 KB Output is correct
23 Correct 74 ms 71880 KB Output is correct
24 Correct 270 ms 71760 KB Output is correct
25 Correct 199 ms 71680 KB Output is correct
26 Correct 228 ms 71512 KB Output is correct
27 Correct 264 ms 71512 KB Output is correct