快速排序的实现

#include <iostream>#include <vector>#include <algorithm>void quicksort(std::vector<int>& vec, int nbegin, int nend){if (nbegin >= nend)return;int nPos = (nbegin + nend) / 2;int nPosV = vec[nPos];std::vector<int> less;std::vector<int> more;for (int i = nbegin; i <= nend; ++i){if (i == nPos)continue;if (vec[i] < vec[nPos])less.push_back(vec[i]);elsemore.push_back(vec[i]);}// ºÏ²¢vector ¿ÕŒä»»Ê±Œäfor (int i = 0; i < less.size(); ++i)vec[nbegin + i] = less[i];vec[nbegin + less.size()] = nPosV;nPos = nbegin + less.size();for (int i = 0; i < more.size(); ++i)vec[nbegin + less.size() + i + 1] = more[i];quicksort(vec, nbegin, nPos);quicksort(vec, nPos + 1, nend);}int main(){std::vector<int> v{ 1, 7, 8, 9, 4, 5, 2 };quicksort(v, 0, v.size() - 1);int a;return 0;}