diff --git a/August-LeetCoding-Challenge/30-Largest-Component-Size-by-Common-Factor/Largest-Component-Size-by-Common-Factor.cs b/August-LeetCoding-Challenge/30-Largest-Component-Size-by-Common-Factor/Largest-Component-Size-by-Common-Factor.cs
new file mode 100644
index 0000000..9538611
--- /dev/null
+++ b/August-LeetCoding-Challenge/30-Largest-Component-Size-by-Common-Factor/Largest-Component-Size-by-Common-Factor.cs
@@ -0,0 +1,51 @@
+public class Solution {
+    int[] par;
+    int[] cnt;
+    public int LargestComponentSize(int[] A) {
+        var n = A.Length;
+        par = new int[n];        
+        cnt = new int[n];
+        var dict = new Dictionary<int, HashSet<int>>();
+        for(int i=0; i<n; i++){
+            int d=2, x=A[i];
+            while(d*d<=x){
+                if(x%d==0){
+                    while(x%d ==0) x/= d;
+                    if(!dict.ContainsKey(d)) 
+                        dict.Add(d, new HashSet<int>());
+                    dict[d].Add(i);
+                }
+                d++;
+            }
+            if(x>1){
+                if(!dict.ContainsKey(x)) 
+                    dict.Add(x, new HashSet<int>());
+                dict[x].Add(i);
+            }
+        }
+        
+        for(int i=0; i<n; i++) par[i] = i;
+        Array.Fill(cnt, 1);
+        int max = 1;
+        foreach(HashSet<int> h in dict.Values){
+            int fir = h.First();
+            foreach(var idx in h){
+                Union(idx, fir);
+                max = Math.Max(cnt[Find(idx)], max);
+            }
+        }
+        return max;
+    }
+    private void Union(int i, int j){
+        int pi = Find(i);
+        int pj = Find(j);
+        if(pi == pj) return ;
+        par[pi] = pj;
+        cnt[pj] += cnt[pi];
+    }
+    
+    private int Find(int i){
+        if(i==par[i]) return i;
+        return par[i] = Find(par[i]);
+    }
+}
\ No newline at end of file
diff --git a/README.md b/README.md
index f7fa720..a349120 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,7 @@ Solutions in various programming languages are provided. Enjoy it.
 27. [Find Right Interval](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/27-Find-Right-Interval)
 28. [Implement Rand10() Using Rand7()](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/28-Implement-Rand10()-Using-Rand7())
 29. [Pancake Sorting](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/29-Pancake-Sorting)
+30. [Largest Component Size by Common Factor](https://github.com/AlgoStudyGroup/Leetcode/tree/master/August-LeetCoding-Challenge/30-Largest-Component-Size-by-Common-Factor)
 
 ## July LeetCoding Challenge
 Click [here](https://leetcode.com/explore/featured/card/july-leetcoding-challenge/) for problem descriptions.