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QOJ
| ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
|---|---|---|---|---|---|---|---|---|---|
| #110578 | #2573. Two Permutations | yllcm | AC ✓ | 90ms | 14120kb | C++17 | 1.5kb | 2023-06-02 21:35:20 | 2023-06-02 21:35:21 |
Judging History
answer
#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define FR first
#define SE second
using namespace std;
inline int read() {
int x = 0; bool op = 0;
char c = getchar();
while(!isdigit(c))op |= (c == '-'), c = getchar();
while(isdigit(c))x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
return op ? -x : x;
}
const int N = 110;
const int P = 1e9 + 7;
void add(int &a, int b) {a += b; a >= P ? a -= P : 0;}
void sub(int &a, int b) {a -= b; a < 0 ? a += P : 0;}
int n, k;
int f[2][N][N * N];
int main() {
n = read(); k = read();
f[1][0][0] = 1;
for(int i = 1; i <= n; i++) {
swap(f[0], f[1]);
for(int x = 0; x <= i; x++)for(int z = 0; z <= i * i; z++)f[1][x][z] = 0;
for(int x = 0; x <= i; x++) {
for(int z = 0; z <= i * i; z++) {
int y = i - 1 - x;
if(f[0][x][z] == 0)continue;
// cout << i << ' ' << x << ' ' << y << ' ' << z << ' ' << f[0][x][z] << endl;
add(f[1][x + 1][z + i], 1ll * (n - x - 2 * y) * f[0][x][z] % P);
add(f[1][x][z], 1ll * (n - x - 2 * y) * (n - x - 2 * y - 1) % P * f[0][x][z] % P);
add(f[1][x + 2][z + 2 * i], 1ll * y * y % P * f[0][x][z] % P);
add(f[1][x + 1][z + i], 2ll * (n - x - 2 * y) * y % P * f[0][x][z] % P);
}
}
}
printf("%d\n", f[1][n][k]);
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 9ms
memory: 14120kb
input:
2 4
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 11ms
memory: 13856kb
input:
3 7
output:
12
result:
ok 1 number(s): "12"
Test #3:
score: 0
Accepted
time: 3ms
memory: 13948kb
input:
4 10
output:
24
result:
ok 1 number(s): "24"
Test #4:
score: 0
Accepted
time: 1ms
memory: 13888kb
input:
4 14
output:
96
result:
ok 1 number(s): "96"
Test #5:
score: 0
Accepted
time: 10ms
memory: 14000kb
input:
5 10
output:
0
result:
ok 1 number(s): "0"
Test #6:
score: 0
Accepted
time: 8ms
memory: 14056kb
input:
5 15
output:
120
result:
ok 1 number(s): "120"
Test #7:
score: 0
Accepted
time: 8ms
memory: 13948kb
input:
5 21
output:
2400
result:
ok 1 number(s): "2400"
Test #8:
score: 0
Accepted
time: 8ms
memory: 13896kb
input:
6 21
output:
720
result:
ok 1 number(s): "720"
Test #9:
score: 0
Accepted
time: 3ms
memory: 13872kb
input:
6 30
output:
25920
result:
ok 1 number(s): "25920"
Test #10:
score: 0
Accepted
time: 8ms
memory: 14052kb
input:
6 27
output:
106560
result:
ok 1 number(s): "106560"
Test #11:
score: 0
Accepted
time: 8ms
memory: 13940kb
input:
20 300
output:
644873710
result:
ok 1 number(s): "644873710"
Test #12:
score: 0
Accepted
time: 8ms
memory: 14000kb
input:
20 139
output:
0
result:
ok 1 number(s): "0"
Test #13:
score: 0
Accepted
time: 18ms
memory: 14008kb
input:
30 470
output:
491424690
result:
ok 1 number(s): "491424690"
Test #14:
score: 0
Accepted
time: 25ms
memory: 13892kb
input:
30 500
output:
8436035
result:
ok 1 number(s): "8436035"
Test #15:
score: 0
Accepted
time: 22ms
memory: 13880kb
input:
40 1000
output:
617159088
result:
ok 1 number(s): "617159088"
Test #16:
score: 0
Accepted
time: 27ms
memory: 13892kb
input:
40 900
output:
729805907
result:
ok 1 number(s): "729805907"
Test #17:
score: 0
Accepted
time: 34ms
memory: 14052kb
input:
60 1830
output:
16340084
result:
ok 1 number(s): "16340084"
Test #18:
score: 0
Accepted
time: 31ms
memory: 13996kb
input:
60 2000
output:
832198921
result:
ok 1 number(s): "832198921"
Test #19:
score: 0
Accepted
time: 78ms
memory: 14000kb
input:
100 5050
output:
437918130
result:
ok 1 number(s): "437918130"
Test #20:
score: 0
Accepted
time: 83ms
memory: 14052kb
input:
100 700
output:
0
result:
ok 1 number(s): "0"
Test #21:
score: 0
Accepted
time: 90ms
memory: 14120kb
input:
100 10000
output:
0
result:
ok 1 number(s): "0"