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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#267056 | #6137. Sub-cycle Graph | zlxFTH | AC ✓ | 190ms | 11204kb | C++17 | 2.1kb | 2023-11-26 21:50:58 | 2023-11-26 21:50:58 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define max_n 511111
#define mo 1000000007
void read(int &p)
{
p = 0;
int k = 1;
char c = getchar();
while (c < '0' || c > '9')
{
if (c == '-')
{
k = -1;
}
c = getchar();
}
while (c >= '0' && c <= '9')
{
p = p * 10 + c - '0';
c = getchar();
}
p *= k;
return;
}
void write_(int x)
{
if (x < 0)
{
putchar('-');
x = -x;
}
if (x > 9)
{
write_(x / 10);
}
putchar(x % 10 + '0');
}
void writesp(int x)
{
write_(x);
putchar(' ');
}
void writeln(int x)
{
write_(x);
putchar('\n');
}
int T,n,m;
int ksm(int a,int b)
{
int pi = 1;
for(;b;b >>= 1,a = (a * a) % mo)
{
if(b & 1)
{
pi = (pi * a) % mo;
}
}
return pi;
}
int jiecheng[max_n],inv[max_n];
int ans = 0;
void solution()
{
read(n),read(m);
if(m > n)
{
puts("0");
return ;
}
if(m == 0)
{
puts("1");
return ;
}
if(n == m)
{
writeln((ksm(2,mo - 2) * jiecheng[n - 1] ) % mo);
return ;
}
ans = 0;
int pi = 1;
for(int i = 1;i + m <= n && i <= m;++i)
{
(ans +=
pi *
jiecheng[m - i] % mo*
jiecheng[n] % mo *
inv[n - m - i] % mo *
inv[m + i] % mo *
jiecheng[m + i] % mo *
inv[i << 1LL] % mo *
inv[m - i] % mo *
jiecheng[m - 1] % mo *
inv[i - 1] % mo *
inv[m - i] % mo) %= mo;
pi = (pi *((i<<1) | 1) % mo);
}
writeln(ans);
}
signed main()
{
jiecheng[0] = 1;
for(int i = 1;i <= 400000;i++)
{
jiecheng[i] = (jiecheng[i - 1] * i) % mo;
}
inv[400000] = ksm(jiecheng[400000],mo - 2);
for(int i = 399999;~i;i--)
{
inv[i] = (inv[i + 1] * (i + 1)) % mo;
}
read(T);
while(T--)
{
solution();
}
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 11064kb
input:
3 4 2 4 3 5 3
output:
15 12 90
result:
ok 3 number(s): "15 12 90"
Test #2:
score: 0
Accepted
time: 190ms
memory: 11204kb
input:
17446 3 0 3 1 3 2 3 3 4 0 4 1 4 2 4 3 4 4 5 0 5 1 5 2 5 3 5 4 5 5 6 0 6 1 6 2 6 3 6 4 6 5 6 6 7 0 7 1 7 2 7 3 7 4 7 5 7 6 7 7 8 0 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 9 0 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 9 9 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 11 0 11 1 11 2 11 3 11 4 11 5 11 6 11 7 11...
output:
1 3 3 1 1 6 15 12 3 1 10 45 90 60 12 1 15 105 375 630 360 60 1 21 210 1155 3465 5040 2520 360 1 28 378 2940 13545 35280 45360 20160 2520 1 36 630 6552 42525 170100 393120 453600 181440 20160 1 45 990 13230 114345 643545 2286900 4762800 4989600 1814400 181440 1 55 1485 24750 273735 2047815 10239075 3...
result:
ok 17446 numbers