题解 | #回型矩阵#

#include<stdio.h>
int main() {
    int N = 1;
    scanf("%d", &N);
    int arr[N][N];
    arr[N / 2][N / 2] = N * N;
    int num = 1;
    for (int n = 0; n < N / 2; n++) {
        for (int i = n; i < N - n - 1; i++) {
            arr[n][i] = num++;
        }
        for (int i = n; i < N - n - 1; i++) {
            arr[i][N - n - 1] = num++;
        }
        for (int j = N - n - 1; j >= n + 1; j--) {
            arr[N - n - 1][j] = num++;
        }
        for (int j = N - n - 1; j >= n + 1; j--) {
            arr[j][n] = num++;
        }
    }
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            printf("%d ", arr[i][j]);
        }
        puts("");
    }
    return 0;
}