[feat ]: leetcode 1971

Signed-off-by: Bo-Wei Chen(BWbwchen) <tim.chenbw@gmail.com>

Author: BWbwchen

leetcode/1971_Find-if-Path-Exists-in-Graph.cpp

@@ -0,0 +1,35 @@
+class Solution {
+public:
+    bool validPath(int n, vector<vector<int>>& edges, int source, int destination) {
+        if (source == destination)
+            return true;
+        stack<int> st;
+        st.push(source);
+        bool ret = false;
+
+        vector<bool> visited(n, false);
+        vector<vector<int>> adj(n);
+        for (auto e: edges) {
+            adj[e[0]].push_back(e[1]);
+            adj[e[1]].push_back(e[0]);
+        }
+
+        while (!st.empty()) {
+            auto top = st.top();
+            st.pop();
+
+            if (!visited[top]) {
+                visited[top] = true;
+                for (auto neigh : adj[top]) {
+                    st.push(neigh);
+                    if (neigh == destination) {
+                        ret = true;
+                        goto found;
+                    }
+                }
+            }
+        }
+found:
+        return ret;
+    }
+};