用C语言写出使用分治法解决规模为n*n(n小于100）矩阵乘法的代码

以下是使用分治法解决规模为n*n(n小于100）矩阵乘法的C语言代码：

#include <stdio.h>

#define N 100

void matrix_mult(int a[][N], int b[][N], int c[][N], int n){
    if(n == 1){
        c[0][0] = a[0][0] * b[0][0];
    } else {
        int i, j, k;
        int a11[N/2][N/2], a12[N/2][N/2], a21[N/2][N/2], a22[N/2][N/2];
        int b11[N/2][N/2], b12[N/2][N/2], b21[N/2][N/2], b22[N/2][N/2];
        int c11[N/2][N/2], c12[N/2][N/2], c21[N/2][N/2], c22[N/2][N/2];
        int p1[N/2][N/2], p2[N/2][N/2], p3[N/2][N/2], p4[N/2][N/2], p5[N/2][N/2], p6[N/2][N/2], p7[N/2][N/2];

        // Divide matrices a and b into four sub-matrices
        for(i = 0; i < n/2; i++){
            for(j = 0; j < n/2; j++){
                a11[i][j] = a[i][j];
                a12[i][j] = a[i][j+n/2];
                a21[i][j] = a[i+n/2][j];
                a22[i][j] = a[i+n/2][j+n/2];

                b11[i][j] = b[i][j];
                b12[i][j] = b[i][j+n/2];
                b21[i][j] = b[i+n/2][j];
                b22[i][j] = b[i+n/2][j+n/2];
            }
        }

        // Calculate p1, p2, p3, p4, p5, p6, p7
        matrix_mult(a11, b11, p1, n/2);
        matrix_mult(a12, b21, p2, n/2);
        matrix_mult(a11, b12, p3, n/2);
        matrix_mult(a12, b22, p4, n/2);
        matrix_mult(a21, b11, p5, n/2);
        matrix_mult(a22, b21, p6, n/2);
        matrix_mult(a21, b12, p7, n/2);

        // Calculate sub-matrices of c
        for(i = 0; i < n/2; i++){
            for(j = 0; j < n/2; j++){
                c11[i][j] = p1[i][j] + p2[i][j];
                c12[i][j] = p3[i][j] + p4[i][j];
                c21[i][j] = p5[i][j] + p6[i][j];
                c22[i][j] = p7[i][j] - p2[i][j] + p4[i][j] + p6[i][j];
            }
        }

        // Combine sub-matrices of c
        for(i = 0; i < n/2; i++){
            for(j = 0; j < n/2; j++){
                c[i][j] = c11[i][j];
                c[i][j+n/2] = c12[i][j];
                c[i+n/2][j] = c21[i][j];
                c[i+n/2][j+n/2] = c22[i][j];
            }
        }
    }
}

int main(){
    int n, i, j;
    int a[N][N], b[N][N], c[N][N];

    printf("Enter the value of n (n should be less than 100):\n");
    scanf("%d", &n);

    printf("Enter the elements of matrix a:\n");
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            scanf("%d", &a[i][j]);
        }
    }

    printf("Enter the elements of matrix b:\n");
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            scanf("%d", &b[i][j]);
        }
    }

    matrix_mult(a, b, c, n);

    printf("Resultant matrix c:\n");
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            printf("%d\t", c[i][j]);
        }
        printf("\n");
    }

    return 0;
}