leetcode/code/lc112.java at master · mJackie/leetcode · GitHub

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package code;

* 112. Path Sum

* 题意：是否存在跟到叶子节点的和为sum

* 难度：Easy

* 分类：

* 思路：

* Tips：lc112, lc113, lc437, lc129, lc124, lc337

* 总结一下 lc112 找跟到叶子和为sum的路径是否存在

* lc113 把lc112的路径找出来

* lc437 是任意一条向下走的路径

* lc129 计算所有的和

* lc124 任意一条路径

* lc337 树的dp

public class lc112 {

public class TreeNode {

int val;

TreeNode left;

TreeNode right;

TreeNode(int x) {

val = x;

}

public boolean hasPathSum(TreeNode root, int sum) {

if(root==null) return false;

if(root.val==sum&&root.left==null&&root.right==null) return true;

return hasPathSum(root.left, sum-root.val)||hasPathSum(root.right, sum-root.val);

}

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