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  • (LeetCode)二叉树中和为某一值的路径

    原体例如以下:

    Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

    For example:
    Given the below binary tree and sum = 22,
                  5
                 / 
                4   8
               /   / 
              11  13  4
             /        
            7    2      1
    

    return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

    我的代码:

    public class Solution {
        public boolean mark = false;
        public boolean hasPathSum(TreeNode root, int sum) {
            if (root == null) {
    			return false;
    		}
    		Stack<Integer> path = new Stack<Integer>();
    		int currentSum = 0;
    		findPath(root, sum, path, currentSum);
    		return mark;
        }
        public void findPath(TreeNode root, int sum, Stack<Integer> path, int currentSum)
    	{
    		currentSum += root.val;
    		path.push(root.val);
    		boolean isLeaf = root.left==null&&root.right==null;
    		if(currentSum==sum&&isLeaf)
    		{
    			mark = true;
    		}
    		if(root.left != null)
    		{
    			findPath(root.left,sum,path,currentSum);
    		}
    		if(root.right != null)
    		{
    			findPath(root.right,sum,path,currentSum);
    		}
    		
    		path.pop();
    	}
    }


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  • 原文地址:https://www.cnblogs.com/liguangsunls/p/7191431.html
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