zoukankan      html  css  js  c++  java
  • [hihoCoder] 题外话·堆

    A direct applicatin of the heap data structure. Specifically, a max heap is used. The required functions include insertion of a node to the heap and extraction of the maximum element of the heap. Each time you insert or remove an element to or from the heap, you need to maintain the max heap property.

    The code is as follows.

    If you want to learn more about heap, you may refer to this passage.

     1 #include <iostream>
     2 #include <vector>
     3 
     4 using namespace std;
     5 
     6 class Heap {
     7 public:
     8     Heap() {
     9         data.clear();
    10     }
    11 
    12     inline int parent(int idx) {
    13         return (idx - 1) >> 1;
    14     }
    15 
    16     inline int left(int idx) {
    17         return (idx << 1) + 1;
    18     }
    19 
    20     inline int right(int idx) {
    21         return (idx << 1) + 2;
    22     }
    23 
    24     void max_heapify(int idx) {
    25         int largest = idx;
    26         int l = left(idx), r = right(idx);
    27         if (l < (int)data.size() && data[l] > data[largest]) largest = l;
    28         if (r < (int)data.size() && data[r] > data[largest]) largest = r;
    29         if (largest != idx) {
    30             swap(data[idx], data[largest]);
    31             max_heapify(largest);
    32         }
    33     }
    34 
    35     void insert(int elem) {
    36         data.push_back(elem);
    37         int idx = data.size() - 1;
    38         while (idx >= 0 && parent(idx) >= 0 && data[parent(idx)] < data[idx]) {
    39             swap(data[parent(idx)], data[idx]);
    40             idx = parent(idx);
    41         }
    42     }
    43 
    44     int extract_max(void) {
    45         int maximum = data[0];
    46         swap(data[0], data[data.size() - 1]);
    47         data.erase(data.end() - 1, data.end());
    48         max_heapify(0);
    49         return maximum;
    50     }
    51 
    52 private:
    53     vector<int> data;
    54 };
    55 
    56 int main(void) {
    57     int events;
    58     while (scanf("%d", &events) != EOF) {
    59         Heap sugars;
    60         for (int i = 0; i < events; i++) {
    61             char order[2];
    62             scanf("%s", order);
    63             if (order[0] == 'A') {
    64                 int sugar;
    65                 scanf("%d", &sugar);
    66                 sugars.insert(sugar);
    67             }
    68             else printf("%d
    ", sugars.extract_max());
    69         }
    70     }
    71     return 0;
    72 }
  • 相关阅读:
    14.会场安排问题(L4)
    图形化调试工具DDD
    sking
    全排列
    DNS
    一种排序
    多边形重心问题
    街区最短路径问题
    Fibonacci数
    python url解析
  • 原文地址:https://www.cnblogs.com/jcliBlogger/p/4558659.html
Copyright © 2011-2022 走看看