剑指 Offer 33. 二叉搜索树的后序遍历序列

Posted 2021-12-10 小布丁value

class Solution {
    public boolean verifyPostorder(int[] postorder) {
      return   recur(postorder,0,postorder.length-1);
    }
    public boolean recur(int [] postorder,int i,int j){
        if(i>=j) return true;//左子树为空的情况
        int p=i;
        while(postorder[p]<postorder[j]) p++;
       int m=p;
        while(postorder[p]>postorder[j]) p++;
        return  p==j&&recur(postorder,i,m-1)&&recur(postorder,m,j-1);
    }
}