package q118

func generate(numRows int) [][]int {
	buf := make([]int, numRows*(1+numRows)/2)
	p := 0
	take := func(n int) []int {
		ret := buf[p : p+n]
		p = p + n
		return ret
	}

	ret := make([][]int, 0, numRows)

	for i := 1; i <= numRows; i++ {
		row := take(i)
		row[0] = 1
		row[len(row)-1] = 1
		for j := 1; j < len(row)-1; j++ {
			row[j] = ret[i-2][j-1] + ret[i-2][j]
		}
		ret = append(ret, row)
	}
	return ret
}

var _ = generate