mergesort

#include <bits/stdc++.h>
using namespace std;
vector<int> a;
void print() {
    for(auto x: a) cout << x << " ";
    cout << endl;
}
void merge(int l, int mid, int h) {
    cout<<"merging between "<<l<<" & "<<h<<" with mid "<<mid<<" : ";
    int i, j, k, n1, n2;
    n1 = mid - l + 1;
    n2 = h - mid;
    vector<int> b(n1), c(n2);
    for (i = 0; i < n1; i++)
        b[i] = a[l + i];
    for (j = 0; j < n2; j++)
        c[j] = a[mid + 1 + j];
    i = j = 0;
    k = l;
    while (i < n1 && j < n2) {
        if (b[i] <= c[j]) a[k++] = b[i++];
        else a[k++] = c[j++];
    }

    while (i < n1) a[k++] = b[i++];

    while (j < n2) a[k++] = c[j++];

    print();
}
void merge_sort(int l, int h) {
    int mid;
    if (l < h) {
        mid = (l + h) / 2;
        merge_sort(l, mid);
        merge_sort(mid + 1, h);
        merge(l, mid, h);
    }
}
int main() {
    int n;
    cout << "enter size & elements of the array \n";
    cin >> n;
    a.resize(n);
    for (auto &x: a) cin >> x;
    merge_sort(0, n - 1);
    cout << "\nmerge sorted array ";
    for (auto x: a) cout<<x<<" ";
    return 0;
}