WA#9#10 求助

约旦-高斯消元法

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>

#define LL long long
#define DB double

using namespace std;

const int kN = 105;
const DB kEps = 1e-16;

int n, sum;
DB a[kN][kN], ans[kN];

signed main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i) {  
        for (int j = 1;j <= n + 1; ++j) {
            scanf("%lf", &a[i][j]);
        }
    }
    for (int i = 1; i <= n; ++i) {
        int p = i;
        for (int j = i + 1; j <= n; ++j) {
            if(fabs(a[j][i]) > fabs(a[p][i])) {
                swap(p, j);
            }
        }
        if(fabs(a[p][i]) < kEps) {continue;}
        if (p != i) {   
            for (int j = i; j <= n + 1; ++j) {
                swap(a[p][j], a[i][j]);
            }
        }
        DB div = a[i][i]; 
        for (int j = i; j <= n + 1; ++j) {
            a[i][j] /= div;
        }
        for (int j = 1; j <= n; ++j) {
            if(j != i) {
                DB w = a[j][i] / a[i][i];
                for (int k = i; k <= n + 1; ++k) {
                    a[j][k] -= a[i][k] * w;
                }
            }
        }
        sum++;
    }
    for (int i = 1; i <= n; ++i) {
        ans[i] = a[i][n + 1];
    }
    if(sum < n) {
        for (int i = 1; i <= n; ++i) {
            if(fabs(ans[i]) < kEps && fabs(a[i][n + 1]) > kEps) {
                printf("-1\n");return 0;
            }
        }
        printf("0\n");return 0;
    }
    for (int i = 1; i <= n; ++i) {
        printf("x%d=", i);
        printf("%.2lf\n", ans[i]);
    }
    return 0;
}
/*
2
0 2 3
0 0 0
*/