Graph Valid Tree

Author: sachuverma

Leetcode Daily Challenge/August-2021/Graph Valid Tree.cpp

@@ -0,0 +1,56 @@
+/*
+Graph Valid Tree
+==================
+
+You have a graph of n nodes labeled from 0 to n - 1. You are given an integer n and a list of edges where edges[i] = [ai, bi] indicates that there is an undirected edge between nodes ai and bi in the graph.
+
+Return true if the edges of the given graph make up a valid tree, and false otherwise.
+
+Example 1:
+Input: n = 5, edges = [[0,1],[0,2],[0,3],[1,4]]
+Output: true
+
+Example 2:
+Input: n = 5, edges = [[0,1],[1,2],[2,3],[1,3],[1,4]]
+Output: false
+ 
+Constraints:
+1 <= 2000 <= n
+0 <= edges.length <= 5000
+edges[i].length == 2
+0 <= ai, bi < n
+ai != bi
+There are no self-loops or repeated edges.
+*/
+
+class Solution {
+public:
+    void dfs(int curr, vector<vector<int>>& adj, vector<int>& vis, int& count) {
+        count++;
+        for(int child: adj[curr]) {
+            if(vis[child] == 0) {
+                vis[child] = 1;
+                dfs(child, adj, vis, count);
+            }
+        }
+    }
+    
+    bool validTree(int n, vector<vector<int>>& edges) {
+        int m = edges.size();
+        if(m != n-1) return false;
+        
+        vector<vector<int>> adj(n, vector<int>(0));
+        
+        for(auto& edge: edges) {
+            adj[edge[0]].push_back(edge[1]);
+            adj[edge[1]].push_back(edge[0]);
+        }
+        
+        int count = 0;
+        vector<int> vis(n);
+        vis[0] = 1;
+        
+        dfs(0, adj, vis, count);
+        return count == n;
+    }
+};

Leetcode Daily Challenge/August-2021/README.md

@@ -24,6 +24,7 @@
 | 19. | [Maximum Product of Splitted Binary Tree](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/615/week-3-august-15th-august-21st/3903/) | [cpp](./19.%20Maximum%20Product%20of%20Splitted%20Binary%20Tree.cpp) |
 | 20. | [Valid Sudoku](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/615/week-3-august-15th-august-21st/3904/)                            |                  [cpp](./20.%20Valid%20Sudoku.cpp)                   |
 | 21. | [Sudoku Solver](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/615/week-3-august-15th-august-21st/3905/)                            |                  [cpp](./20Sudoku%20Solver.%20.cpp)                   |
+|  | [Graph Valid Tree](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/616/week-4-august-22nd-august-28th/3906/)                            |                  [cpp](./Graph%20Valid%20Tree.cpp)                   |
 | 23. | [Two Sum IV - Input is a BST](https://leetcode.com/explore/featured/card/august-leetcoding-challenge-2021/616/week-4-august-22nd-august-28th/3908/)                            |                  [cpp](./23.%20Two%20Sum%20IV%20-%20Input%20is%20a%20BST.cpp)                   |
 | 24. | [Complex Number Multiplication](https://leetcode.com/explore/featured/card/august-leetcoding-challenge-2021/616/week-4-august-22nd-august-28th/3917/)                            |                  [cpp](./24.%20Complex%20Number%20Multiplication.cpp)                   |
 | 25. | [Sum of Square Numbers](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge-2021/616/week-4-august-22nd-august-28th/3918/)                            |                  [cpp](./25.%20Sum%20of%20Square%20Numbers.cpp)                   |