Unaccepted 100pts求助（悬2关）

rt，请指出我源代码的问题，不要直接发给我你的AC代码。

#include<bits/stdc++.h>
using namespace std;
int n;
double a[1005][1005];
double check[1005];
void Consumption() {
    // int row = 1;
    for(int i = 1;i <= n;++i) {
        for(int j = i + 1;j <= n;++j) {
            if(fabs(a[j][i]) > 1e-2) {for(int k = 1;k <= n + 1;++k) swap(a[i][k],a[j][k]); break;}
        }
        if(fabs(a[i][i]) < 1e-12) continue;
        for(int j = 1;j <= n;++j) {
            if(j == i) continue;
            double rt = a[j][i] / a[i][i];
            for(int k = i;k <= n + 1;++k) a[j][k] -= a[i][k] * rt;
        }
        // ++row;
    }
    bool flag2 = 0;
    for(int i = 1;i <= n;++i){
        bool flag = 0;
        for(int j = 1;j <= n;++j){
             if(fabs(a[i][j]) > 1e-12) flag = 1;
        }
        if(!flag){
            flag2 = 1;
            if(fabs(a[i][n + 1]) > 1e-12) return cout << "-1\n",void();
        } 
    }
    if(flag2) {
        return cout << "0\n",void();    
    }
    for(int i = 1;i <= n;++i) cout << "x" << i << "=" << fixed << setprecision(2) << double(a[i][n + 1] / a[i][i]) << '\n';
    return ;
}
signed main(){
    cin >> n;
    for(int i = 1;i <= n;++i) for(int j = 1;j <= n + 1;++j) cin >> a[i][j];
    return Consumption(),0;
}