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#include "leetcode.h"
class Solution {
public:
int removeStones(vvd(int) & stones) {
int n = stones.size(), c = 0;
unordered_map<int, vector<int>> rows, cols;
for (int i = 0; i < n; ++i) {
rows[stones[i][0]].push_back(i);
cols[stones[i][1]].push_back(i);
}
unordered_set<int> seen;
function<int(int)> dfs;
dfs = [&](int i) -> int {
if (seen.count(i))
return 0;
seen.insert(i);
int j = stones[i][0], k = stones[i][1];
for (auto r : rows[j])
dfs(r);
for (auto c : cols[k])
dfs(c);
return 1;
};
for (int i = 0; i < n; ++i)
c += dfs(i);
return n - c;
}
};
int main() {
Solution obj;
vvd(int) stones = {{0, 0}, {0, 1}, {1, 0}, {1, 2}, {2, 1}, {2, 2}};
cout << obj.removeStones(stones);
}
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