QOJ.ac
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 |
|---|---|---|---|---|---|---|---|---|---|
| #502836 | #2573. Two Permutations | yingxilin | AC ✓ | 77ms | 12284kb | C++14 | 895b | 2024-08-03 15:06:08 | 2024-08-03 15:06:09 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
const int mod = (1e9+7);
int n,k,now=0,last=0,dp[2][110][10010];
int main()
{
cin>>n>>k;
dp[0][0][0]=1;
for(int i=1;i<=n;i++)
{
now=1-now,last=1-now;
memset(dp[now],0,sizeof dp[now]);
int val=i;
for(int j=0;j<=min(n,i);j++) for(int p=0;p<=k;p++){
if(!dp[last][j][p]) continue;
dp[now][j][p]=(dp[now][j][p]+dp[last][j][p])%mod;
int res=i*2-j*2-2;
if(res>1 && val*2+p<=k)
dp[now][j+2][p+val*2]=(dp[now][j+2][p+val*2]+1ll*dp[last][j][p]*res/2%mod*res/2)%mod;
if(res>=0 && val+p<=k)
dp[now][j+1][p+val]=(dp[now][j+1][p+val]+1ll*dp[last][j][p]*(1+res))%mod;
}
}
int ans=dp[now][n][k];
for(int i=2;i<=n;i++) ans=1ll*ans*i%mod;
cout<<ans;
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 12228kb
input:
2 4
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 2ms
memory: 12220kb
input:
3 7
output:
12
result:
ok 1 number(s): "12"
Test #3:
score: 0
Accepted
time: 2ms
memory: 12208kb
input:
4 10
output:
24
result:
ok 1 number(s): "24"
Test #4:
score: 0
Accepted
time: 2ms
memory: 12284kb
input:
4 14
output:
96
result:
ok 1 number(s): "96"
Test #5:
score: 0
Accepted
time: 2ms
memory: 12128kb
input:
5 10
output:
0
result:
ok 1 number(s): "0"
Test #6:
score: 0
Accepted
time: 0ms
memory: 12136kb
input:
5 15
output:
120
result:
ok 1 number(s): "120"
Test #7:
score: 0
Accepted
time: 3ms
memory: 12196kb
input:
5 21
output:
2400
result:
ok 1 number(s): "2400"
Test #8:
score: 0
Accepted
time: 3ms
memory: 12156kb
input:
6 21
output:
720
result:
ok 1 number(s): "720"
Test #9:
score: 0
Accepted
time: 0ms
memory: 12280kb
input:
6 30
output:
25920
result:
ok 1 number(s): "25920"
Test #10:
score: 0
Accepted
time: 3ms
memory: 12224kb
input:
6 27
output:
106560
result:
ok 1 number(s): "106560"
Test #11:
score: 0
Accepted
time: 0ms
memory: 12188kb
input:
20 300
output:
644873710
result:
ok 1 number(s): "644873710"
Test #12:
score: 0
Accepted
time: 4ms
memory: 12276kb
input:
20 139
output:
0
result:
ok 1 number(s): "0"
Test #13:
score: 0
Accepted
time: 3ms
memory: 12140kb
input:
30 470
output:
491424690
result:
ok 1 number(s): "491424690"
Test #14:
score: 0
Accepted
time: 3ms
memory: 12204kb
input:
30 500
output:
8436035
result:
ok 1 number(s): "8436035"
Test #15:
score: 0
Accepted
time: 9ms
memory: 12280kb
input:
40 1000
output:
617159088
result:
ok 1 number(s): "617159088"
Test #16:
score: 0
Accepted
time: 9ms
memory: 12156kb
input:
40 900
output:
729805907
result:
ok 1 number(s): "729805907"
Test #17:
score: 0
Accepted
time: 13ms
memory: 12280kb
input:
60 1830
output:
16340084
result:
ok 1 number(s): "16340084"
Test #18:
score: 0
Accepted
time: 12ms
memory: 12212kb
input:
60 2000
output:
832198921
result:
ok 1 number(s): "832198921"
Test #19:
score: 0
Accepted
time: 60ms
memory: 12204kb
input:
100 5050
output:
437918130
result:
ok 1 number(s): "437918130"
Test #20:
score: 0
Accepted
time: 22ms
memory: 12208kb
input:
100 700
output:
0
result:
ok 1 number(s): "0"
Test #21:
score: 0
Accepted
time: 77ms
memory: 12160kb
input:
100 10000
output:
0
result:
ok 1 number(s): "0"