【模板】高斯消元

#include<bits/stdc++.h>
#define N 205
using namespace std;
const double eps=1e-8;
int n;
double a[N][N],del;
bool gauss(){
    for(int i=1;i<=n;i++){
        int k=i;
        for(int j=i+1;j<=n;j++)if(fabs(a[j][i])>fabs(a[k][i]))k=j;
        if(fabs(del=a[k][i])<eps)return 0;
        for(int j=i;j<=n+1;j++)swap(a[i][j],a[k][j]);
        for(int j=i;j<=n+1;j++)a[i][j]/=del;
        for(k=1;k<=n;k++)if(k!=i){
            del=a[k][i];
            for(int j=i;j<=n+1;j++)a[k][j]-=a[i][j]*del;
        }
    }
    return 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]);
    bool flag=gauss();
    if(!flag)puts("No Solution");
    else for(int i=1;i<=n;i++)printf("%.2lf\n",a[i][n+1]);
    return 0;
}