LintCode:线段树的查询

LintCode:线段树的查询

""" Definition of SegmentTreeNode: class SegmentTreeNode: def __init__(self, start, end, max): self.start, self.end, self.max = start, end, max self.left, self.right = None, None """

class Solution: 
    # @param root, start, end: The root of segment tree and 
    # an segment / interval
    # @return: The maximum number in the interval [start, end]
    def query(self, root, start, end):
        # write your code here
        if root == None:
            return 0
        if root.start > end or root.end < start or start > end:
            return 0
        if root.start >= start and root.end <= end:
            return root.max

        mid = root.start + (root.end - root.start) / 2
        left_max = self.query(root.left, start, min(mid, end))
        right_max = self.query(root.right, max(start, mid), end)
        return max(left_max, right_max)

Java

/** * Definition of SegmentTreeNode: * public class SegmentTreeNode { * public int start, end, max; * public SegmentTreeNode left, right; * public SegmentTreeNode(int start, int end, int max) { * this.start = start; * this.end = end; * this.max = max * this.left = this.right = null; * } * } */
public class Solution {
    /** *@param root, start, end: The root of segment tree and * an segment / interval *@return: The maximum number in the interval [start, end] */
    public int query(SegmentTreeNode root, int start, int end) {
        // write your code here
        if(root == null){
            return 0;
        }
        if(root.start > end || root.end < start || start > end){
            return 0;
        }
        if(root.start >= start && root.end <= end){
            return root.max;
        }

        int mid = root.start + (root.end - root.start)/2;
        int leftMax = query(root.left, start, Math.min(mid, end));
        int rightMax = query(root.right, Math.max(start, mid), end);

        return Math.max(leftMax, rightMax);
    }
}