quick sort, merge sort

include "stdafx.h"
#include <iostream>
#include <map>
#include <unordered_set>
#include <string>
#include <algorithm>
 
using namespace std;
 
void mergesortrec(vector<int> * data, int low, int high) {
    // base case : if one left, return without any work
    if (low == high) {
        return;
    }
    // starting from length 2 ; split with 0 and 1 , 
    int mid = (low + high) / 2;
    mergesortrec(data, low, mid);
    mergesortrec(data, mid + 1, high);
    vector<int> buf;
    buf.reserve(high - low + 1);
    int highit = mid + 1;
    int lowit = low;
    for (int i = low; i <= high; i++) {
        if (lowit <= mid && highit <= high) {
            if (data->at(highit) > data->at(lowit)) {
                buf.push_back(data->at(lowit));
                lowit++;
            }
            else {
                buf.push_back(data->at(highit));
                highit++;
            }
            
        }else if (highit == high + 1) {
            buf.push_back(data->at(lowit));
            lowit++;
        }else if (lowit == mid + 1) {
            buf.push_back(data->at(highit));
            highit++;
        }
    }
    for (int i = low; i <= high; i++) {
        data->at(i) = buf.at(i - low);
    }
}
 
void mergesort(vector<int> * data) {
    mergesortrec(data, 0, data->size() - 1);
}
 
int main() {
    vector<int> v1 = { 5,3,1,9,10,4,2,8,8,7,6 };
    mergesort(&v1);
    for (int i : v1) {
        cout << i << " ";
    }
    while(1){}
    return 0;
}
 
//---
 
void quicksortrec(vector<int> * v1, int low, int high) {
    if (low == high) {
        return;
    }
    vector<int> buf;
    buf.reserve(high - low);
    int pivot = v1->at(high - 1);
    buf.push_back(pivot);
    int count = 0;
    for (int i = low; i < high - 1; i++) {
        if (pivot < v1->at(i)) {
            buf.push_back(v1->at(i));
        }
        else {
            buf.insert(buf.begin(), v1->at(i));
            count++;
        }
    }
    for (int i = low; i < high; i++) {
        v1->at(i) = buf.at(i - low);
    }
    quicksortrec(v1, low, low+count);
    quicksortrec(v1, low+count + 1, high);
}
 
void quicksort(vector<int> * v1) {
    return quicksortrec(v1,0,v1->size());
}
 
int main1212() {
    vector<int> v1 = { 3,1,4,10,3,13,9,8,7 };
    quicksort(&v1);
    for (int i : v1) {
        cout << i << " ";
    }
    while(1){}
    return 0;
}