题解 | 回型矩阵

#include <stdio.h>
int main() {
    int n = 0;
    scanf("%d", &n);
    int a[n][n];
    int top = 0;
    int bottom = n - 1;
    int left = 0;
    int right = n - 1;
    int i = 0;
    int num = 1;

    while (top <= bottom)
    {
        //填充丄侧
        for (i=left; i<=right; ++i)
        {
            a[top][i] = num;
            ++num;        
        }
        ++top;

        //填充右侧
        for (i=top; i<=bottom; ++i)
        {
            a[i][right] = num;
            ++num;
        }
        --right;

        //填充下侧
        for (i=right; i>=left; --i)
        {
            a[bottom][i] = num;
            ++num;
        }
        --bottom;

        //填充左侧
        for (i=bottom; i>=top; --i)
        {
            a[i][left] = num;
            ++num;
        }
        ++left;
    }

    for (i=0; i<n; ++i)
    {
        for (int j=0; j<n; ++j)
        {
            printf("%d ", a[i][j]);
        }
        printf("\n");
    }

    return 0;
}