堆排序

/**
 * 排序算法之堆排序
**/
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

void adjust(vector<int>& vec, int len, int index) {
    int left = 2 * index + 1;
    int right = 2 * index + 2;
    int maxIdx = index; //代表父子三个数中最大数的下标
    if (left < len && vec[left] > vec[maxIdx]) maxIdx = left;
    if (right < len && vec[right] > vec[maxIdx]) maxIdx = right;
    if (maxIdx != index) {
        swap(vec[maxIdx], vec[index]);
        adjust(vec, len, maxIdx);
    }

}

void heapSort(vector<int>& vec, int size) {
    for (int i = size / 2 - 1; i >= 0; i--) {//从最后一个非叶节点开始进行堆调整
        adjust(vec, size, i);
    }

    for (int i = size - 1; i >= 1; i--) {
        swap(vec[0], vec[i]);
        adjust(vec, i, 0);
    }

}

int main() {
    vector<int> vec = {2,1,3,5,4};
    int len = vec.size();
    heapSort(vec, len);
    for (auto x : vec) {
        cout << x << endl;
    }
    return 0;
}