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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#503552 | #2573. Two Permutations | FRZ_29 | AC ✓ | 487ms | 21968kb | C++14 | 1.5kb | 2024-08-03 19:56:39 | 2024-08-03 19:56:40 |
Judging History
answer
#include <iostream>
#include <cstring>
#include <cstdio>
typedef long long LL;
using namespace std;
inline int RD() {
int x = 0, f = 1;
char ch = getchar();
while (ch < '0' || ch > '9') {
if (ch == '-') f = -1;
ch = getchar();
}
while (ch >= '0' && ch <= '9')
x = (x << 3) + (x << 1) + ch - '0', ch = getchar();
return x * f;
}
const int N = 105;
const LL mod = 1e9 + 7;
#define MOD(x) (((x) + mod) % mod)
#define LF(i, __l, __r) for (int i = __l; i <= __r; i++)
#define RF(i, __r, __l) for (int i = __r; i >= __l; i--)
int n, k;
LL f[2][N][N * N]; // 第 1 维为处理到了第 i 个数,第 2 维已经处理好了 j 对数,第 3 维为现在数的和。
// 表示方案数
int main() {
n = RD(), k = RD();
f[0][0][0] = 1;
LF(i, 1, n) {
memset(f[i & 1], 0, sizeof(f[i & 1]));
LF(j, 0, i - 1) {
LF(l, 0, k) {
LL x = j, y = (i - 1) - j, z = n - x - y * 2;
LL &a = f[i & 1][j + 1][l + i],
&b = f[i & 1][j + 2][l + 2 * i],
&c = f[i & 1][j][l],
d = f[(i - 1) & 1][j][l];
a = MOD(MOD(d * z) + a);
a = MOD(MOD(d * MOD(y * MOD(2 * z))) + a);
b = MOD(MOD(d * y) * y + b);
c = MOD(MOD(d * z) * (z - 1) + c);
}
}
}
printf("%lld", f[n & 1][n][k]);
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 4ms
memory: 21876kb
input:
2 4
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 0ms
memory: 21968kb
input:
3 7
output:
12
result:
ok 1 number(s): "12"
Test #3:
score: 0
Accepted
time: 2ms
memory: 21832kb
input:
4 10
output:
24
result:
ok 1 number(s): "24"
Test #4:
score: 0
Accepted
time: 2ms
memory: 21884kb
input:
4 14
output:
96
result:
ok 1 number(s): "96"
Test #5:
score: 0
Accepted
time: 0ms
memory: 21888kb
input:
5 10
output:
0
result:
ok 1 number(s): "0"
Test #6:
score: 0
Accepted
time: 0ms
memory: 21904kb
input:
5 15
output:
120
result:
ok 1 number(s): "120"
Test #7:
score: 0
Accepted
time: 3ms
memory: 21960kb
input:
5 21
output:
2400
result:
ok 1 number(s): "2400"
Test #8:
score: 0
Accepted
time: 0ms
memory: 21908kb
input:
6 21
output:
720
result:
ok 1 number(s): "720"
Test #9:
score: 0
Accepted
time: 0ms
memory: 21816kb
input:
6 30
output:
25920
result:
ok 1 number(s): "25920"
Test #10:
score: 0
Accepted
time: 5ms
memory: 21808kb
input:
6 27
output:
106560
result:
ok 1 number(s): "106560"
Test #11:
score: 0
Accepted
time: 5ms
memory: 21884kb
input:
20 300
output:
644873710
result:
ok 1 number(s): "644873710"
Test #12:
score: 0
Accepted
time: 7ms
memory: 21820kb
input:
20 139
output:
0
result:
ok 1 number(s): "0"
Test #13:
score: 0
Accepted
time: 11ms
memory: 21808kb
input:
30 470
output:
491424690
result:
ok 1 number(s): "491424690"
Test #14:
score: 0
Accepted
time: 11ms
memory: 21896kb
input:
30 500
output:
8436035
result:
ok 1 number(s): "8436035"
Test #15:
score: 0
Accepted
time: 15ms
memory: 21824kb
input:
40 1000
output:
617159088
result:
ok 1 number(s): "617159088"
Test #16:
score: 0
Accepted
time: 23ms
memory: 21808kb
input:
40 900
output:
729805907
result:
ok 1 number(s): "729805907"
Test #17:
score: 0
Accepted
time: 48ms
memory: 21896kb
input:
60 1830
output:
16340084
result:
ok 1 number(s): "16340084"
Test #18:
score: 0
Accepted
time: 56ms
memory: 21832kb
input:
60 2000
output:
832198921
result:
ok 1 number(s): "832198921"
Test #19:
score: 0
Accepted
time: 266ms
memory: 21804kb
input:
100 5050
output:
437918130
result:
ok 1 number(s): "437918130"
Test #20:
score: 0
Accepted
time: 62ms
memory: 21900kb
input:
100 700
output:
0
result:
ok 1 number(s): "0"
Test #21:
score: 0
Accepted
time: 487ms
memory: 21876kb
input:
100 10000
output:
0
result:
ok 1 number(s): "0"