feat: Solve leetcode/leetcoding_challenge/2025/jan2025/week5/redundant_connection.cpp

Author: htbkoo

src/onlinePlatform/leetcode/leetcoding_challenge/2025/jan2025/week5/redundant_connection.cpp

@@ -0,0 +1,67 @@
+#include <algorithm>
+#include <vector>
+#include <queue>
+#include <set>
+#include <limits>
+#include <map>
+#include <unordered_set>
+#include <unordered_map>
+#include <iterator>
+#include <sstream>
+#include <iostream> // includes cin to read from stdin and cout to write to stdout
+using namespace std; // since cin and cout are both in namespace std, this saves some text
+
+class Solution {
+private:
+    vector<int> parents;
+    vector<int> sizes;
+    
+    int find(int x) {
+        if (parents[x] != x) {
+            parents[x] = find(parents[x]);
+        }
+        return parents[x];
+    }
+    
+    bool unionSet(int x, int y) {
+        x = find(x);
+        y = find(y);
+        if (x == y) {
+            // the edge is redundant
+            // as the 2 nodes are already unioned
+            return false;
+        }
+        
+        if (sizes[x] < sizes[y]) {
+            int temp = x;
+            x = y;
+            y = temp;
+        }
+        
+        parents[y] = x;
+        sizes[x] += sizes[y];
+        return true;
+    }
+    
+public:
+    vector<int> findRedundantConnection(vector<vector<int>>& edges) {
+        int n = edges.size();
+        vector<int> answer;
+        
+        parents = vector<int>();
+        for (int i = 0; i < n; ++i) {
+            parents.push_back(i);
+        }
+        sizes = vector<int>(n, 1);        
+        
+        for (auto edge: edges) {
+            auto a = edge[0];
+            auto b = edge[1];
+            if (!unionSet(a - 1, b - 1)) {
+                answer = {a, b};
+            }
+        }
+        
+        return answer;
+    }
+};