#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const lint mod = 1e9 + 7;
int R, C, N;
lint f[3007][3007], fact[9000003], inv_fact[9000003], res;
lint modexp(lint a, lint b) {
lint ans = 1;
while(b > 0) {
if(b % 2) ans = ans * a % mod;
a = a * a % mod, b /= 2;
}
return ans;
}
lint F(int x, int y) {
if(x > R || y > C) return 0;
if(x == R && y == C) return 1;
if(f[x][y]) return f[x][y];
lint fw = F(x + 1, y) * fact[y] % mod;
lint fh = F(x, y + 1) * fact[x] % mod;
return f[x][y]= (fw + fh) % mod;
}
void set_fact(int n) {
fact[0] = 1;
for(int i = 1; i <= n; i++)
fact[i] = fact[i - 1] * i % mod;
inv_fact[n] = modexp(fact[n], mod - 2);
for(int i = n; i >= 1; i--)
inv_fact[i - 1] = inv_fact[i] * i % mod;
}
lint nCr(int n, int r) {
if(r > n) return 0;
return fact[n] * inv_fact[n - r] % mod * inv_fact[r] % mod;
}
int main() {
scanf("%d%d%d", &R, &C, &N);
set_fact(R * C);
int x1 = R + 1, y1 = C + 1, x2 = 0, y2 = 0;
for(int i = 0; i < N; i++) {
int x, y;
scanf("%d%d", &x, &y);
x1 = min(x1, x), y1 = min(y1, y);
x2 = max(x2, x), y2 = max(y2, y);
}
res = F(x2 - x1 + 1, y2 - y1 + 1) % mod;
res = res * fact[(x2 - x1 + 1) * (y2 - y1 + 1) - N] % mod;
res = res * nCr(R - (x2 - x1 + 1), x1 - 1) % mod;
res = res * nCr(C - (y2 - y1 + 1), y1 - 1) % mod;
printf("%lld\n", res);
return 0;
}
Compilation message
mascots.cpp: In function 'int main()':
mascots.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
46 | scanf("%d%d%d", &R, &C, &N);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~
mascots.cpp:52:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
52 | scanf("%d%d", &x, &y);
| ~~~~~^~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
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 |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
332 KB |
Output is correct |
11 |
Correct |
1 ms |
332 KB |
Output is correct |
12 |
Correct |
1 ms |
332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
972 KB |
Output is correct |
2 |
Correct |
3 ms |
2036 KB |
Output is correct |
3 |
Correct |
5 ms |
3148 KB |
Output is correct |
4 |
Correct |
36 ms |
21940 KB |
Output is correct |
5 |
Correct |
37 ms |
21040 KB |
Output is correct |
6 |
Correct |
53 ms |
21120 KB |
Output is correct |
7 |
Correct |
33 ms |
28908 KB |
Output is correct |
8 |
Correct |
68 ms |
62944 KB |
Output is correct |
9 |
Correct |
159 ms |
141220 KB |
Output is correct |
10 |
Correct |
350 ms |
185028 KB |
Output is correct |
11 |
Correct |
256 ms |
162248 KB |
Output is correct |
12 |
Correct |
147 ms |
124868 KB |
Output is correct |
13 |
Correct |
15 ms |
12456 KB |
Output is correct |
14 |
Correct |
154 ms |
141148 KB |
Output is correct |
15 |
Correct |
375 ms |
207308 KB |
Output is correct |
16 |
Correct |
273 ms |
145032 KB |
Output is correct |
17 |
Correct |
165 ms |
145636 KB |
Output is correct |
18 |
Correct |
367 ms |
204512 KB |
Output is correct |