模板整理之线性同余方程组（逆元法）

#include<cstdio>#include<cstdlib>#include<cstring>#include<algorithm>#include<iostream>using namespace std;int x,y,n,coe[100],remain[100],mod[100];class X{public:int x,y;X(int a,int b){x=a;y=b;return;}};int ex_gcd(int num1,int num2){if(!num2){x=1;y=0;return num1;}int ans=ex_gcd(num1,num2);int tmp=x;x=y;y=tmp-(num1/num2)*x;return ans;}int get_inverse(int num,int m){ex_gcd(num,m);return (x%m+m)%m;}//注:只有num和m互质时可以求逆元X Liner_Cont_Equatoins(){int ans=0,M=1,cur_coe,cur_remain,cur_mod;for(int i=0;i<=n-1;i++){cur_coe=coe[i];cur_remain=remain[i]-ans*coe[i];cur_mod=mod[i];int d=ex_gcd(cur_coe,cur_mod);if(cur_remain%d) return X(-1,-1);//方程组无解cur_coe/=d;cur_remain/=d;cur_mod/=d;int t;int inverse=get_inverse(cur_coe,cur_mod);t=(inverse*cur_remain)%cur_mod;t=(t+cur_mod)%cur_mod;ans+=M*t;M*=cur_mod;ans%=M;}return X(ans,M);}int main(){return 0;}