(最小)堆的实现

最新推荐文章于 2022-12-25 16:38:14 发布

原创最新推荐文章于 2022-12-25 16:38:14 发布 · 239 阅读

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#堆

int len = 0;
vector<int> heap = {0};
void init(vector<int> h) {
  len = 0;
  h.clear();
  h.push_back(0);
}
void put(int x) {
  len++;
  heap.push_back(x);
  int son = len;
  while ( son != 1 && heap[son/2] > heap[son])  {
    int tmp = heap[son/2];
    heap[son/2] = heap[son];
    heap[son] = tmp;
    son = son / 2 ;
  }
}
int del() {
  if (len == 0) {
    return 0;
  }
  int res = heap[1];
  heap[1] = heap[len];
  heap.pop_back();
  len--;
  int fa = 1;
  int son = 2;
  while (fa <= len/2 || fa*2+1 <= len) {
    son = fa * 2;
    if ((fa*2+1) > len || heap[fa*2] < heap[fa*2+1]) {
      son = fa*2;
    } else {
      son = fa * 2 + 1;
    }
    if (heap[fa] > heap[son]) {
      swap(heap[fa], heap[son]);
      fa = son;
    } else {
      break;
    }
  }
  return res;
}

put是向堆中插入元素，del是取出最小（堆顶）的元素。