098_验证二叉搜索树

中等

class Solution {
    public boolean isValidBST(TreeNode root) {
        return inSpread(root,(long)Integer.MIN_VALUE - 1,(long)Integer.MAX_VALUE + 1);
    }
    boolean inSpread(TreeNode node,long left,long right){
        if(node.val <= left || node.val >= right){
            return false;
        }
        if(node.left != null){
            if(!inSpread(node.left, left, node.val)) return false;
        }
        if(node.right != null){
            if(!inSpread(node.right, node.val, right)) return false;
        }
        return true;
    }
}

递归判断左右节点是否满足条件，传入参数为左右区间的值，小于等于left或大于等于right都是false