leetcode[119]:Pascal's Triangle II

Pascal’s Triangle II

Given an index k, return the kth row of the Pascal’s triangle.

For example, given k = 3,
Return [1,3,3,1].

Note:
Could you optimize your algorithm to use only O(k) extra space?

/**
 * Return an array of size *returnSize.
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* getRow(int rowIndex, int* returnSize) {
    int *result;
    int i,j,tmp,tmp2;
    rowIndex++;
    * returnSize = rowIndex;
    result= (int*)malloc(sizeof(int*)*rowIndex);
    result[0]=1;
    tmp=1;
    for(i=1;i<rowIndex;i++)
    {
        for(j=1;j<i;j++)
        {
            tmp2=result[j];
            result[j]=result[j]+tmp;
            tmp=tmp2;
        }
        result[j]=1;
    }
    return result;
}

防止覆蓋，需要保留上次的值。