Given numRows, generate the first numRows of Pascal's triangle.
For example, given numRows = 5,
Return
[
[1],
[1,1],
[1,2,1],
[1,3,3,1],
[1,4,6,4,1]
]
分析
很简单的二维数组，杨辉三角，上一行的两数相加的和放在下一行。
/**
* Return an array of arrays.
* The sizes of the arrays are returned as *columnSizes array.
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
*/
int** generate(int numRows, int** columnSizes) {
int **ans=(int **)malloc(sizeof(int*)*numRows);
*columnSizes=(int*)malloc(sizeof(int)*numRows);
for(int i=0;i<numRows;i++)
{
ans[i]=(int*)malloc(sizeof(int)*(i+1));
(*columnSizes)[i]=(i+1);
ans[i][0]=1;
for(int j=1;j<i;j++)
ans[i][j]=ans[i-1][j]+ans[i-1][j-1];
ans[i][i]=1;
}
return ans;
}
