leetcode 118 杨辉三角

/**
 * 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** generate(int numRows, int* returnSize, int** returnColumnSizes){
     int **answer=(int**)malloc(sizeof(int*)*numRows);
     (*returnColumnSizes)=(int*)malloc(sizeof(int)*numRows);
     int i=0,j=0;
     for(i=1;i<=numRows;i++)
     {
         answer[i-1]=(int*)malloc(sizeof(int)*i);
         answer[i-1][0]=1;
         for(j=1;j<i-1;j++)
         {
             answer[i-1][j]=answer[i-2][j-1]+answer[i-2][j];
         }
         answer[i-1][i-1]=1;
         (*returnColumnSizes)[i-1]=i;
     }
     *returnSize=numRows;
     return answer;
}