3160. Find the Number of Distinct Colors Among the Balls

JAVA

• class Solution {
      public int[] queryResults(int limit, int[][] queries) {
          Map<Integer, Integer> g = new HashMap<>();
          Map<Integer, Integer> cnt = new HashMap<>();
          int m = queries.length;
          int[] ans = new int[m];
          for (int i = 0; i < m; ++i) {
              int x = queries[i][0], y = queries[i][1];
              cnt.merge(y, 1, Integer::sum);
              if (g.containsKey(x) && cnt.merge(g.get(x), -1, Integer::sum) == 0) {
                  cnt.remove(g.get(x));
              }
              g.put(x, y);
              ans[i] = cnt.size();
          }
          return ans;
      }
  }

C++

• class Solution {
  public:
      vector<int> queryResults(int limit, vector<vector<int>>& queries) {
          unordered_map<int, int> g;
          unordered_map<int, int> cnt;
          vector<int> ans;
          for (auto& q : queries) {
              int x = q[0], y = q[1];
              cnt[y]++;
              if (g.contains(x) && --cnt[g[x]] == 0) {
                  cnt.erase(g[x]);
              }
              g[x] = y;
              ans.push_back(cnt.size());
          }
          return ans;
      }
  };

PYTHON

• class Solution:
      def queryResults(self, limit: int, queries: List[List[int]]) -> List[int]:
          g = {}
          cnt = Counter()
          ans = []
          for x, y in queries:
              cnt[y] += 1
              if x in g:
                  cnt[g[x]] -= 1
                  if cnt[g[x]] == 0:
                      cnt.pop(g[x])
              g[x] = y
              ans.append(len(cnt))
          return ans