题解 | #二叉树中和为某一值的路径(一)#

//利用栈进行dfs深度优先搜索，采用pair嵌套
/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */

#include <utility>
class Solution {
public:
    /**
     * 
     * @param root TreeNode类 
     * @param sum int整型 
     * @return bool布尔型
     */
    bool hasPathSum(TreeNode* root, int sum) {
        // write code here
        if (root==NULL) {
            return false;
        }
        stack<pair<TreeNode*, int>> s;
        s.push({root,sum-root->val});
        while (!s.empty()) {
            auto temp=s.top();
            s.pop();
            if (temp.first->left==NULL&&temp.first->right==NULL&&temp.second==0) {
                return true;
            }
            if (temp.first->left) {
                s.push({temp.first->left,temp.second-temp.first->left->val});
            }
            if (temp.first->right) {
                s.push({temp.first->right,temp.second-temp.first->right->val});
            }

        }
        return false;

    }
};