Update Find if Path Exists in Graph - Leetcode 1971.cpp

Author: gahogg

Find if Path Exists in Graph - Leetcode 1971/Find if Path Exists in Graph - Leetcode 1971.cpp

@@ -1,3 +1,5 @@
+// Recursive DFS
+
 #include <vector>
 #include <unordered_map>
 #include <unordered_set>
@@ -34,3 +36,84 @@ class Solution {
         return false;
     }
 };
+
+// Iterative DFS With Stack
+
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+#include <stack>
+
+using namespace std;
+
+class Solution {
+public:
+    bool validPath(int n, vector<vector<int>>& edges, int source, int destination) {
+        if (source == destination) return true;
+
+        unordered_map<int, vector<int>> graph;
+        for (const auto& edge : edges) {
+            graph[edge[0]].push_back(edge[1]);
+            graph[edge[1]].push_back(edge[0]);
+        }
+
+        unordered_set<int> seen;
+        stack<int> stack;
+        stack.push(source);
+        seen.insert(source);
+
+        while (!stack.empty()) {
+            int node = stack.top();
+            stack.pop();
+            if (node == destination) return true;
+
+            for (int neighbor : graph[node]) {
+                if (seen.find(neighbor) == seen.end()) {
+                    seen.insert(neighbor);
+                    stack.push(neighbor);
+                }
+            }
+        }
+        return false;
+    }
+};
+
+// BFS With Queue
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+#include <queue>
+
+using namespace std;
+
+class Solution {
+public:
+    bool validPath(int n, vector<vector<int>>& edges, int source, int destination) {
+        if (source == destination) return true;
+
+        unordered_map<int, vector<int>> graph;
+        for (const auto& edge : edges) {
+            graph[edge[0]].push_back(edge[1]);
+            graph[edge[1]].push_back(edge[0]);
+        }
+
+        unordered_set<int> seen;
+        queue<int> queue;
+        queue.push(source);
+        seen.insert(source);
+
+        while (!queue.empty()) {
+            int node = queue.front();
+            queue.pop();
+            if (node == destination) return true;
+
+            for (int neighbor : graph[node]) {
+                if (seen.find(neighbor) == seen.end()) {
+                    seen.insert(neighbor);
+                    queue.push(neighbor);
+                }
+            }
+        }
+        return false;
+    }
+};