using System;
using System.Collections.Generic;
class GFG
{
static readonly int N = 4;
static void getCofactor[int [,]A, int [,]temp, int p, int q, int n]
{
int i = 0, j = 0;
for [int row = 0; row < n; row++]
{
for [int col = 0; col < n; col++]
{
if [row != p && col != q]
{
temp[i, j++] = A[row, col];
if [j == n - 1]
{
j = 0;
i++;
}
}
}
}
}
static int determinant[int [,]A, int n]
{
int D = 0;
if [n == 1]
return A[0, 0];
int [,]temp = new int[N, N];
int
sign = 1;
for [int f = 0; f < n; f++]
{
getCofactor[A, temp, 0, f, n];
D += sign * A[0, f] * determinant[temp, n - 1];
sign = -sign;
}
return D;
}
static void adjoint[int [,]A, int [,]adj]
{
if [N == 1]
{
adj[0, 0] = 1;
return;
}
int sign = 1;
int
[,]temp = new int[N, N];
for [int i = 0; i < N; i++]
{
for [int j = 0; j < N; j++]
{
getCofactor[A, temp, i, j, N];
sign = [[i + j] % 2 == 0]? 1: -1;
adj[j, i] = [sign] * [determinant[temp, N - 1]];
}
}
}
static bool inverse[int [,]A, float [,]inverse]
{
int det = determinant[A, N];
if [det == 0]
{
Console.Write["Singular matrix, can't find its inverse"];
return false;
}
int [,]adj = new int[N, N];
adjoint[A, adj];
for [int i = 0; i < N; i++]
for [int j = 0; j < N; j++]
inverse[i, j] = adj[i, j]/[float]det;
return true;
}
static void display[int [,]A]
{
for [int i = 0; i < N; i++]
{
for [int j = 0; j < N; j++]
Console.Write[A[i, j]+ " "];
Console.WriteLine[];
}
}
static void display[float [,]A]
{
for [int i = 0; i < N; i++]
{
for [int j = 0; j < N; j++]
Console.Write["{0:F6} ", A[i, j]];
Console.WriteLine[];
}
}
public static void Main[String[] args]
{
int
[,]A = { {5, -2, 2, 7},
{1, 0, 0, 3},
{-3, 1, 5, 0},
{3, -1, -9, 4}};
int [,]adj = new int[N, N];
float [,]inv = new float[N, N];
Console.Write["Input matrix is :\n"];
display[A];
Console.Write["\nThe Adjoint is :\n"];
adjoint[A, adj];
display[adj];
Console.Write["\nThe Inverse is :\n"];
if [inverse[A, inv]]
display[inv];
}
}