algorithm/Week_02/id_124/LeetCode_783_124.java at master · feixiangcode/algorithm · GitHub

31 lines (27 loc) · 827 Bytes

import common.TreeNode;

import java.util.ArrayList;

import java.util.List;

import java.util.Stack;

public class MinDiffInBST {

public int minDiffInBST(TreeNode root) {

List<Integer> nlist = new ArrayList<>();

Stack<TreeNode> stack = new Stack<>();

TreeNode node = root;

while (node != null || !stack.isEmpty()){

while (node.left != null){

stack.push(node);

node = node.left;

}

if (!stack.isEmpty()){

TreeNode t = stack.pop();

nlist.add(t.val);

node = t.right;

}

int min = Integer.MAX_VALUE;

for (int i = 1; i< nlist.size() ; i++){

min = Math.min(min, nlist.get(i) - nlist.get(i-1));

}

return min;

}

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