NOI.AC
| 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 |
|---|---|---|---|---|---|---|---|---|---|
| #164769 | #2908. count | paul2008 | 100 | 8ms | 5884kb | C++ | 766b | 2022-11-05 19:10:35 | 2022-11-05 19:10:37 |
answer
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int N=2e5+5;
const int Mod=1e9+7;
long long jc[N],invjc[N],sum[N];
long long qsm(int x,int y)
{
if(!y)
return 1;
long long t=qsm(x,y/2);
if(y%2==0)
return t*t%Mod;
return t*t%Mod*x%Mod;
}
long long C(int n,int m)
{
return jc[n]*invjc[n-m]%Mod*invjc[m]%Mod;
}
int main()
{
jc[0]=1;
for(int i=1;i<=200000;i++)
{
jc[i]=jc[i-1]*i%Mod;
sum[i]=(sum[i-1]+i)%Mod;
}
invjc[200000]=qsm(jc[200000],Mod-2);
for(int i=200000;i>=1;i--)
invjc[i-1]=invjc[i]*i%Mod;
int T;
cin >> T;
while(T--)
{
long long n,m;
cin >> n >> m;
printf("%lld\n",C(n+m-2,n-1)*((n*m-1)%Mod)%Mod);
}
return 0;
}
详细
小提示：点击横条可展开更详细的信息
Test #1:
score: 20
Accepted
time: 0ms
memory: 5880kb
input:
10 1 1 2000 1997 117 1647 392 452 959 1883 1046 1627 1398 1124 1372 306 1799 1007 111 1765
output:
0 57631948 737963048 807538931 137760374 398194748 77480423 174938019 583393917 445670336
result:
ok 10 lines
Test #2:
score: 20
Accepted
time: 4ms
memory: 5880kb
input:
10 1 1 2000 1997 1218 1479 350 1244 784 1715 999 92 396 1393 1726 1511 624 756 900 317
output:
0 57631948 610566455 356523655 593949258 665757514 349394180 73375269 50652564 663822508
result:
ok 10 lines
Test #3:
score: 20
Accepted
time: 4ms
memory: 5880kb
input:
10 1 1 100000 99997 36934 50467 5497 37576 83775 15544 23817 68917 33052 49207 59924 39340 2708 2614...
output:
0 73866797 788834869 539491921 582239610 497376436 343937059 324406513 13225836 35059446
result:
ok 10 lines
Test #4:
score: 20
Accepted
time: 0ms
memory: 5884kb
input:
10 1 1 100000 99997 6792 14252 90281 65716 46434 67120 18977 30384 16191 33996 3425 10433 31783 4263...
output:
0 73866797 609230597 213203975 638117274 527713366 525065128 867713025 174019248 375031322
result:
ok 10 lines
Test #5:
score: 20
Accepted
time: 0ms
memory: 5880kb
input:
10 1 1 100000 99994 47270 99792 93093 92620 88764 20724 48143 99711 33293 89038 2816 16811 97638 670...
output:
0 796648553 5720713 279796657 802039459 22848874 23038351 610731858 629891152 812026839
result:
ok 10 lines
