[Algorithm template] Gaussian elimination

Gaussian elimination for solving a linear equation.

Paste the code below:

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#define maxn 150
int n;
double a[maxn][maxn];
using namespace std;
void gau(){
    for(int i=1;i<=n;i++){      
    int line=i;
        for(int j=i+1;j<=n;j++){
            if(fabs(a[line][i])<fabs(a[j][i]))line=j;
        }
        for(int j=1;j<=n+1;j++)swap(a[line][j],a[i][j]);
        if(!a[i][i]){printf("No Solution");return;}
        for(int j=n+1;j>=i+1;j--){
            for(int k=i+1;k<=n;k++){
                a[k][j]-=a[k][i]/a[i][i]*a[i][j];
            }
        }
    }
    for(int i=n;i>=1;i--){
        for(int j=i+1;j<=n;j++){
            a[i][n+1]-=a[j][n+1]*a[i][j];
        }
        a[i][n+1]/=a[i][i];
    }
    for(int i=1;i<=n;i++){
        printf("%.2f\n",a[i][n+1]);
    }
}
int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n+1;j++){
            scanf("%lf",&a[i][j]);
        }
    }
    gau();
}