leetcode

0 class Solution {

1 public:

2 int removeStones(vector<vector<int>> &stones) {

3 unordered_map<int, vector<int>> rows, cols;

4 unordered_set<int> seen;

5

6 for (int s = 0; s < size(stones); ++s)

7 rows[stones[s][0]].push_back(s), cols[stones[s][1]].push_back(s);

8

9 int c = 0;

10 stack<int> st;

11 for (int s = 0; s < size(stones); ++s) {

12 if (seen.count(s)) continue;

13 st.push(s);

14 while (!st.empty()) {

15 int s = st.top();

16 st.pop();

17 if (seen.count(s)) continue;

18 seen.insert(s);

19 int r = stones[s][0], c = stones[s][1];

20 for (auto ss : rows[r])

21 if (!seen.count(ss)) st.push(ss);

22 for (auto ss : cols[c])

23 if (!seen.count(ss)) st.push(ss);

24 }

25 c++;

26 }

27

28 return size(stones) - c;

29 }

30 };