People are different. Some secretly read magazines full of interesting girls' pictures, others create an A-bomb in their
cellar, others like using Windows, and some like difficult mathematical games. Latest marketing research shows, that this
market segment was so far underestimated and that there is lack of such games. This kind of game was thus included into
the KOKODDáKH. The rules follow:
Each player chooses two numbers Ai and Bi and writes them on a slip of paper. Others cannot see the numbers. In a given
moment all players show their numbers to the others. The goal is to determine the sum of all expressions AiBi from all
players including oneself and determine the remainder after division by a given number M. The winner is the one who first
determines the correct result. According to the players' experience it is possible to increase the difficulty by choosing
higher numbers.
You should write a program that calculates the result and is able to find out who won the game.
输入
The input consists of Z assignments. The number of them is given by the single positive integer Z appearing on the first
line of input. Then the assignements follow. Each assignement begins with line containing an integer M (1 <= M <= 45000).
The sum will be divided by this number. Next line contains number of players H (1 <= H <= 45000). Next exactly H lines
follow. On each line, there are exactly two numbers Ai and Bi separated by space. Both numbers cannot be equal zero at
the same time.
输出
For each assingnement there is the only one line of output. On this line, there is a number, the result of expression
(A1B1 + A2B2 + ... + AHBH) mod M.
样例输入
3
16
42 3
3 4
4 5
5 6
36123
1
2374859 3029382
17
1
3 18132
样例输出
2
13195
13
描述
快速取模运算,可以将O(n)的复杂度降低到O(log(n))
代码
#include
using namespace std;
#define LL long long
LL quick(LL a,LL b,LL m){//a^b%m
LL ans=1;
while(b){//当b是奇数
if(b&1){
ans = ans * a % m;
}
b>>=1;
a = a*a%m;
}
return ans;
}
//LL multi(LL a,LL b,LL m){//a*b%m
// LL ans=0;
// while(b){
// if(b&1){
// ans = (ans + a) %m;
// }
// b>>=1;
// a = (a+a)%m;
// }
// return ans;
//}
int main(){
int z,m,h;
LL ai,bi;
LL ans;
scanf("%d",&z);
while(z--){
ans=0;
scanf("%d",&m);
scanf("%d",&h);
for(int i=0;i