947 - Most Stones Removed with Same Row or Column

 JAVA

• class Solution {
      private int[] p;
  
      public int removeStones(int[][] stones) {
          int n = 10010;
          p = new int[n << 1];
          for (int i = 0; i < p.length; ++i) {
              p[i] = i;
          }
          for (int[] stone : stones) {
              p[find(stone[0])] = find(stone[1] + n);
          }
          Set<Integer> s = new HashSet<>();
          for (int[] stone : stones) {
              s.add(find(stone[0]));
          }
          return stones.length - s.size();
      }
  
      private int find(int x) {
          if (p[x] != x) {
              p[x] = find(p[x]);
          }
          return p[x];
      }
  }

C++

• class Solution {
  public:
      vector<int> p;
  
      int removeStones(vector<vector<int>>& stones) {
          int n = 10010;
          p.resize(n << 1);
          for (int i = 0; i < p.size(); ++i) p[i] = i;
          for (auto& stone : stones) p[find(stone[0])] = find(stone[1] + n);
          unordered_set<int> s;
          for (auto& stone : stones) s.insert(find(stone[0]));
          return stones.size() - s.size();
      }
  
      int find(int x) {
          if (p[x] != x) p[x] = find(p[x]);
          return p[x];
      }
  };