输入

3
0.00 0.00 1.00 1.00
0.00 0.00 0.00 0.00 
0.00 0.00 0.00 2.00

输出

-1

而这份AC代码输出0

#include<bits/stdc++.h>
using namespace std;
const int N = 55;
const double eps = 1e-8;
double a[N][N];
int n;
int gauss(){
	int r,c;
	for(c = 0,r = 0;c<n;c++){
		int t = r;
		for(int i = r;i<n;i++)
			if(fabs(a[i][c])>fabs(a[t][c]))t = i;
		if(fabs(a[t][c])<eps)continue;
		for(int i = c;i<=n;i++)swap(a[r][i],a[t][i]);
		for(int i = n;i>=c;i--)a[r][i]/=a[r][c];
		for(int i = r+1;i<n;i++){
			if(fabs(a[i][c])>eps){
				for(int j = n;j>=c;j--){
					a[i][j] -= a[i][c] * a[r][j];
				}
			}
		}
		r++;
	}
	if(r<n){
		for(int i = r;i<n;i++){
			if(fabs(a[i][n])>eps)return 2;
		return 1;
		}
	}
	for(int i = n-1;i>=0;i--)
		for(int j = i+1;j<n;j++)a[i][n] -= a[i][j]*a[j][n];
	return 0;
}
int main(){
	scanf("%d",&n);
	for(int i = 0;i<n;i++)
		for(int j = 0;j<=n;j++)scanf("%lf",&a[i][j]);
	int t = gauss();
	if(t==2)return puts("-1"),0;
	if(t==1)return puts("0"),0;
	for(int i = 0;i<n;i++){
		cout<<"x"<<i+1<<"=";
		printf("%.2lf\n",a[i][n]);
	}
	return 0;
}