SegmentTree Build

Question

Build tree： 1.以数组的下标来建立线段树 2.以数值来建立线段树

Thought

Solution

def build(self, start, end, A):
        if start > end:
            return None
        root = SegmentTreeNode(start, end, 0)

        if start < end:
            mid = (start + end) / 2
            root.left = self.build(start, mid, A)
            root.right = self.build(mid+1, end, A)
            root.count = min(root.left.count, root.right.count)
        else:
            root.count = A[start]

        return root