Wa on #3 #11

#include<bits/stdc++.h>
#define ll long long
#define For(i,l,r) for(int i=l;i<=r;++i)
#define FOR(i,r,l) for(int i=r;i>=l;--i)
#define eqs 1e-10

using namespace std;

const int N = 105;

int n;

double a[N][N];

signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> n;
  For(i,1,n) {
    For(j,1,n+1) {
      cin >> a[i][j];
    }
  }
  for (int i = 1; i <= n - 1; ++i) {
    For(j,i+1,n) if(fabs(a[i][i]) < fabs(a[j][i])) swap(a[i], a[j]);
    if(fabs(a[i][i]) < eqs) continue;
    For(j,i+1,n) {
      double w = a[j][i] / a[i][i];
      For(l,i,n+1) {
        a[j][l] -= w * a[i][l];
      }
    }
  }
  for (int i = n; i >= 2; --i) {
    if(fabs(a[i][i]) < eqs) continue;
    FOR(j,i-1,1) {
      double w = a[j][i] / a[i][i];
      For(l,i,n+1) {
        a[j][l] -= w * a[i][l];
      }
    }
  }
  For(i,1,n) if(fabs(a[i][i]) < eqs && fabs(a[i][n+1]) > eqs) return puts("-1"), 0; 
  For(i,1,n) if(fabs(a[i][i]) < eqs && fabs(a[i][n+1]) < eqs) return puts("0"), 0;
  For(k,1,n) {
    printf("x%d=%.2lf\n", k, a[k][n+1] / a[k][k]);
  }
  return 0;
}

/*
9 3       2         2 
0 3.66667 6.77778   2.77778 
0 0       -1.15152  2.75758 


9 0       2         -13.5526 
0 3.66667 0         19.0088 
0 0       -1.15152  2.75758
 */