112.路径总和

方法：广度优先搜索

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public boolean hasPathSum(TreeNode root, int targetSum) {
        if(root == null){
            return false;
        }
        Queue<TreeNode> queNode = new LinkedList<TreeNode>();
        Queue<Integer> queVal = new LinkedList<Integer>();
        queNode.offer(root);
        queVal.offer(root.val);
        while(!queNode.isEmpty()){
            TreeNode now = queNode.poll();
            int tmp = queVal.poll();
            if(now.left == null && now.right == null){
                if(tmp == targetSum){
                    return true;
                }
                continue;
            }
            if(now.left!= null){
                queNode.offer(now.left);
                queVal.offer(now.left.val+tmp);
            }
            if(now.right!=null){
                queNode.offer(now.right);
                queVal.offer(now.right.val + tmp);
            }
        }
        return false;
    }
}