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947.cpp
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947.cpp
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__________________________________________________________________________________________________
sample 24 ms submission
static const auto ___ = [](){
std::cout.sync_with_stdio(false);
cin.tie(0);
return 0;
}();
class _disjoint_set {
vector<int> _parent;
int _size;
public:
_disjoint_set(int n) {
_parent.reserve(n);
for (int i = 0; i < n; i++)
_parent.push_back(i);
_size = n;
}
int find(int i) {
if (i != _parent[i])
_parent[i] = _parent[find(_parent[i])];
return _parent[i];
}
void join(int i, int j) {
int ri = find(i), rj = find(j);
if (ri != rj) {
_parent[ri] = rj;
_size--;
}
}
inline int size() { return _size; }
};
class Solution {
public:
int removeStones(vector<vector<int>>& stones) {
_disjoint_set ds(stones.size());
vector<pair<int, int>> vp;
for (int i = 0; i < stones.size(); i++)
vp.emplace_back(stones[i][0], i);
sort(vp.begin(), vp.end());
for (int i = 1; i < vp.size(); i++)
if (vp[i].first == vp[i - 1].first)
ds.join(vp[i].second, vp[i - 1].second);
vp.clear();
for (int i = 0; i < stones.size(); i++)
vp.emplace_back(stones[i][1], i);
sort(vp.begin(), vp.end());
for (int i = 1; i < vp.size(); i++)
if (vp[i].first == vp[i - 1].first)
ds.join(vp[i].second, vp[i - 1].second);
return stones.size() - ds.size();
}
};
__________________________________________________________________________________________________
sample 13488 kb submission
class Solution {
public:
int cnt = 0;
int removeStones(vector<vector<int>>& stones) {
int n = stones.size();
vector<int> parent(n);
cnt = n;
for (int i = 0; i < n; i++)
parent[i] = i;
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
if (stones[i][0] == stones[j][0] || stones[i][1] == stones[j][1]) {
uni(parent, i, j);
}
}
}
return (n - cnt);
}
void uni(vector<int>& parent, int x, int y) {
x = find(parent, x);
y = find(parent, y);
if (x == y) return;
parent[x] = y;
cnt--;
}
int find(vector<int>& parent, int x) {
if (x != parent[x]) parent[x] = find(parent, parent[x]);
return parent[x];
}
};
__________________________________________________________________________________________________