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Solution_508.java
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45 lines (37 loc) · 1.09 KB
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package com.hilbert25.leetcode;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
/**
* @author : hilbert25
* @version 创建时间：2017年4月12日 下午12:47:03 LeetCode com.hilbert25.leetcode
* Solution_508
*/
public class Solution_508 {
public static void main(String[] args) {
// TODO Auto-generated method stub
}
public class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) {
val = x;
}
}
public int[] findFrequentTreeSum(TreeNode root) {
Map<Integer, Integer> sum = new HashMap<Integer, Integer>();
calSumOfSubTree(sum, root);
int maxOccurs = sum.values().stream().max(Comparator.naturalOrder()).orElse(-1);
return sum.entrySet().stream().filter(e -> e.getValue() == maxOccurs).mapToInt(e -> e.getKey()).toArray();
}
public int calSumOfSubTree(Map<Integer, Integer> sum, TreeNode node) {
if (node == null)
return 0;
else {
int value = calSumOfSubTree(sum, node.left) + calSumOfSubTree(sum, node.right) + node.val;
sum.compute(value, (k, v) -> v == null ? 1 : v + 1);
return value;
}
}
}