求后序遍历是否为标准二叉搜索树
二叉搜索树的后序遍历序列
http://www.nowcoder.com/questionTerminal/a861533d45854474ac791d90e447bafd
上下界约束法
import java.util.*; public class Solution { public boolean VerifySquenceOfBST(int [] sequence) { if(sequence.length==0){ return false; } Stack<Integer> stackmin = new Stack<Integer>(); int maxLimit = Integer.MAX_VALUE; stackmin.push(sequence[sequence.length-1]); for(int i = sequence.length-1 ; i >=0 ; i--){ if(sequence[i] > maxLimit) { return false; }else{ while (!stackmin.isEmpty()&&sequence[i]<stackmin.peek()){ maxLimit = stackmin.peek(); stackmin.pop(); } stackmin.push(sequence[i]); } } return true; } }