leetcode 54. Spiral Matrix

原题：

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

代码如下：

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* spiralOrder(int** matrix, int matrixRowSize, int matrixColSize) {
    int amount = (matrixRowSize)*(matrixColSize);
    int* res=(int*)malloc(sizeof(int)*amount);
    //printf("%d",amount);
    int count=0;
    int l,r,t,b;
    l=0;
    t=0;
    r=matrixColSize-1;
    b=matrixRowSize-1;
    int flag=0;
    while(count!=amount)
    {
      
        if(flag%4==0)
        {
            for(int k=l;k<=r;k++)
            {
                *(res+count)=matrix[t][k];
                count++;
                
            }
            printf("%d",count);
            t++;
        }
        else if(flag%4==1)
        {
            for(int k=t;k<=b;k++)
            {
                *(res+count)=matrix[k][r];
                count++;
            }
            r--;
        }
        else if(flag%4==2)
        {
            for(int k=r;k>=l;k--)
            {
                *(res+count)=matrix[b][k];
                count++;
            }
            b--;
        }
        else
        {
            for(int k=b;k>=t;k--)
            {
                *(res+count)=matrix[k][l];
                count++;
            }
            l++;
        }
        flag++;
    }
    return res;
}

设定四个边界进行条件判断就好。