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_0437_PathSumIII.java
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_0437_PathSumIII.java
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package com.diguage.algorithm.leetcode;
import com.diguage.algorithm.util.TreeNode;
import java.util.Arrays;
import java.util.Objects;
import static com.diguage.algorithm.util.TreeNodeUtils.buildTree;
/**
* = 437. Path Sum III
*
* https://leetcode.com/problems/path-sum-iii/[Path Sum III - LeetCode]
*
* @author D瓜哥, https://www.diguage.com/
* @since 2020-01-28 23:06
*/
public class _0437_PathSumIII {
/**
* Runtime: 23 ms, faster than 10.40% of Java online submissions for Path Sum III.
* Memory Usage: 39.1 MB, less than 90.91% of Java online submissions for Path Sum III.
*
* Copy from: https://leetcode-cn.com/problems/path-sum-iii/solution/leetcode-437-path-sum-iii-by-li-xin-lei/[LeetCode 437 Path Sum III - 路径总和 III - 力扣(LeetCode)]
*/
public int pathSum(TreeNode root, int sum) {
if (Objects.isNull(root)) {
return 0;
}
return pathSum(root.left, sum) + pathSum(root.right, sum) + childPathSum(root, sum);
}
private int childPathSum(TreeNode root, int sum) {
if (Objects.isNull(root)) {
return 0;
}
int result = 0;
if (root.val == sum) {
result++;
}
result += childPathSum(root.left, sum - root.val);
result += childPathSum(root.right, sum - root.val);
return result;
}
public static void main(String[] args) {
_0437_PathSumIII solution = new _0437_PathSumIII();
int r1 = solution.pathSum(buildTree(Arrays.asList(10, 5, -3, 3, 2, null, 11, 3, -2, null, 1)), 8);
System.out.println((r1 == 3) + " : " + r1);
}
}