//

// GenerateMatrix.c

// AlgorithmForC

//

// Created by gjh on 2021/1/30.

//

#include "GenerateMatrix.h"

/**

* 59. 螺旋矩阵 II

* Return an array of arrays of size *returnSize.

* The sizes of the arrays are returned as *returnColumnSizes array.

* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().

*/

int** generateMatrix(int n, int* returnSize, int** returnColumnSizes) {

// 返回数组的行数 为 n

* returnSize = n;

// 返回数组的列数

* returnColumnSizes = (int*)malloc(sizeof(int) * n);

// 返回数组

int** result = (int**)malloc(sizeof(int*) * n);

for (int i = 0; i < n; i++) {

result[i] = (int*)malloc(sizeof(int) * n);

(*returnColumnSizes)[i] = n;

}

// 定义上下左右边界

int top = 0, right = n - 1, bottom = n - 1, left = 0;

// 起始数, 和结束数

int cur = 1, end = n * n;

while (cur <= end) {

// 从左到右,从上到下开始排列

for (int i = left; i <= right; i++) {

result[top][i] = cur++;

}

// 内缩

top++;

// 右侧, 从上到下

for (int i = top; i <= bottom; i++) {

result[i][right] = cur++;

}

right--;

// 底部, 从右到左

for (int i = right; i >= left; i--) {

result[bottom][i] = cur++;

}

bottom--;

// 左边 ,从下到上

for (int i = bottom; i >= top; i--) {

result[i][left] = cur++;

}

left++;

}

return result;

}