代码随想录算法训练营第十四天|513.找树左下角的值、112. 路径总和-优快云博客

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代码随想录算法训练营第十四天

513.找树左下角的值

class Solution {
public:
    int findBottomLeftValue(TreeNode* root) {
        queue<TreeNode*> que;
        int result;
        que.push(root);
        while(!que.empty()) {
            int size = que.size();
            for(int i = 0; i < size; i++) {
                TreeNode* node = que.front();
                que.pop();
                if(i == 0) result = node->val;
                if(node->left) que.push(node->left);
                if(node->right) que.push(node->right);
            }
        }
        return result;
    }
};

112. 路径总和

题目链接
 文章讲解
 视频讲解

class Solution {
public:
    bool hasPathSum(TreeNode* root, int targetSum) {
        if(root == nullptr) return false;
        stack<pair<TreeNode*, int>> st;
        st.push(pair<TreeNode*, int>(root, root->val));
        while(!st.empty()) {
            pair<TreeNode*, int> node = st.top();
            st.pop();
            if(!node.first->left && !node.first->right && targetSum == node.second) return true;
            if(node.first->left) {
                st.push(pair<TreeNode*, int>(node.first->left, node.second + node.first->left->val));
            }
            if(node.first->right) {
                st.push(pair<TreeNode*, int>(node.first->right, node.second + node.first->right->val));
            }
        }
        return false;
    }
};