day 4

Author: sachuverma

Leetcode Daily Challenge/August-2021/04. Path Sum II.cpp

@@ -0,0 +1,71 @@
+/*
+Path Sum II
+===========
+
+Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where each path's sum equals targetSum.
+
+A leaf is a node with no children.
+
+Example 1:
+Input: root = [5,4,8,11,null,13,4,7,2,null,null,5,1], targetSum = 22
+Output: [[5,4,11,2],[5,8,4,5]]
+
+Example 2:
+Input: root = [1,2,3], targetSum = 5
+Output: []
+
+Example 3:
+Input: root = [1,2], targetSum = 0
+Output: []
+
+Constraints:
+The number of nodes in the tree is in the range [0, 5000].
+-1000 <= Node.val <= 1000
+-1000 <= targetSum <= 1000
+*/
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+
+class Solution
+{
+public:
+    void dfs(TreeNode *root, vector<vector<int>> &ans, vector<int> &path, int target, int curr)
+    {
+        if (!root->left && !root->right)
+        {
+            path.push_back(root->val);
+            if (curr + root->val == target)
+                ans.push_back(path);
+            path.pop_back();
+            return;
+        }
+
+        path.push_back(root->val);
+        if (root->left)
+            dfs(root->left, ans, path, target, curr + root->val);
+        if (root->right)
+            dfs(root->right, ans, path, target, curr + root->val);
+        path.pop_back();
+    }
+
+    vector<vector<int>> pathSum(TreeNode *root, int targetSum)
+    {
+        if (!root)
+            return {};
+
+        vector<vector<int>> ans;
+        vector<int> curr;
+        dfs(root, ans, curr, targetSum, 0);
+        return ans;
+    }
+};

Leetcode Daily Challenge/August-2021/README.md

@@ -4,4 +4,5 @@
 | :-: | :------------------------------------------------------------------------------------------------------------------------------------------- | :--------------------------------------------: |
 | 1.  | [Making A Large Island](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/613/week-1-august-1st-august-7th/3835/) | [cpp](./01.%20Making%20A%20Large%20Island.cpp) |
 | 2.  | [Two Sum](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/613/week-1-august-1st-august-7th/3836/)               |          [cpp](./02.%20Two%20Sum.cpp)          |
-| 3.  | [Subsets I](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/613/week-1-august-1st-august-7th/3837/)             |        [cpp](./03.%20Subsets%20II.cpp)         |
+| 3.  | [Subsets II](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/613/week-1-august-1st-august-7th/3837/)            |        [cpp](./03.%20Subsets%20II.cpp)         |
+| 4.  | [Path Sum II](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/613/week-1-august-1st-august-7th/3838/)           |       [cpp](./04.%20Path%20Sum%20II.cpp)       |