快速排序

/**
 * 排序算法之快速排序
**/
#include <iostream>
#include <vector>

using namespace std;

void sortKuaiPai(vector<int>& vec, int low, int high) {
    if (low >= high) return ;

    int first = low;
    int last = high;
    int key = vec[first];

    while (first < last) {
        while (first < last && vec[last] >= key) {
            last--;
        }
        if (first < last) {
            vec[first++] = vec[last];
        }

        while (first < last && vec[first <= key])
            first++;
        if (first < last)
            vec[last--] = vec[first];
    }
    vec[first] = key;
    sortKuaiPai(vec, low, first- 1);
    sortKuaiPai(vec, first + 1, high);
}

int main() {
    vector<int> vec = {2,1,3,5,4};
    int len = vec.size() - 1;
    sortKuaiPai(vec, 0, len);
    for (int i = 0; i < vec.size(); ++i) {
        cout << vec[i] << endl;
    }
    return 0;
}