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Binary Min-Heap.cpp
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Binary Min-Heap.cpp
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#include <vector>
struct minHeap {
std :: vector <int64_t> h{0}, entry{0};
std :: vector <uint32_t> pos{0};
void swapNodes(uint32_t u, uint32_t v) {
std :: swap(h[u], h[v]);
std :: swap(pos[entry[u]], pos[entry[v]]);
std :: swap(entry[u], entry[v]);
}
void upHeap(uint32_t v) {
while (1 < v and h[v] < h[v >> 1]) {
swapNodes(v, v >> 1);
v >>= 1;
}
}
void Insert(int64_t x) {
entry.emplace_back(pos.size());
pos.emplace_back(h.size());
h.emplace_back(x);
upHeap(h.size() - 1);
}
void eraseMin() {
swapNodes(1, h.size() - 1);
h.pop_back();
entry.pop_back();
uint32_t v = 1, son;
while ((v << 1) < h.size()) {
son = v << 1;
if ((son | 1) < h.size() and h[son | 1] < h[son])
son |= 1;
if (h[v] <= h[son])
return;
swapNodes(v, son);
v = son;
}
}
void Erase(uint32_t k) {
h[pos[k]] = -1;
upHeap(pos[k]);
eraseMin();
}
int64_t getMin() {
return h[1];
}
};