c求逆矩阵的代码_二维矩阵求逆

#include<stdio.h>
#include<iostream>
#pragma warning(disable : 4996)

using namespace std;

const int maxn=105;

int juzhen[maxn][maxn],n;
int ans[maxn][maxn];
int book[maxn];
int nx(int n)
{
	int sum = 0;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < i; j++)
		{
			if (book[j] > book[i]) sum++;
		}
	}
	if (sum & 1) return -1;
	return 1;
}
int yuzi_ans;
void dfs(int yuzi[maxn][maxn], int sum, int pos,int n) {
	if (sum == n ) {
		int s = 1;
		for (int i = 0; i < n; i++) s *= yuzi[i][book[i]];
		yuzi_ans += nx(n) * s;
		return;
	}
	for (int i = 0; i < n; i++)
	{
		if (pos >> i & 1) continue;
		pos = pos | 1 << i;
		book[sum] = i;
		dfs(yuzi,sum + 1,pos,n);
		pos = pos ^ 1 << i;
	}
}
int f(int yuzi[maxn][maxn],int n) {
	yuzi_ans = 0;
	dfs(yuzi, 0, 0,n);
	return yuzi_ans;
}
void nijuzhen() {
	int yuzi[maxn][maxn];
	int bansui[maxn][maxn];
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			int p = 0;
			for (int k = 0; k < n - 1; k++) {
				if (p == i) {
					p++;
				}
				int q = 0;
				for (int r = 0; r < n - 1; r++) {
					if (q == j) {
						q++;
					}
					yuzi[k][r] = juzhen[p][q++];
				}
				p++;
			}
			int flag = 1;
			if ((i + j) & 1) flag = -1;
			bansui[j][i] = f(yuzi,n-1)*flag;
		}
	}
	printf("伴随矩阵为：\n");
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			printf("%d ", bansui[i][j]);
		}
		printf("\n");
	}
	printf("原矩阵对应的行列式的值为：\n");
	printf("%d", f(juzhen, n));
}

int main()
{
	printf("请输入矩阵阶数\n");
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			scanf("%d", &juzhen[i][j]);
	nijuzhen();
	return 0;
}