归并排序算法

#include "bits/stdc++.h"

using namespace std;

const int N = 1e5 + 10;
int n;
int a[N];

void merge(int l, int mid, int r) {
	vector v;
	int i = l, j = mid + 1;
	while(i <= mid && j <= r) {
		if(a[i] < a[j]) {
			v.push_back(a[i]);
			i++;
		}
		else {
			v.push_back(a[j]);
			j++;
		}
	} 
	
	while(i <= mid) {
		v.push_back(a[i]);
		i++;
	}
	
	while(j <= r) {
		v.push_back(a[j]);
		j++;
	}
	
	for(i = l, j = 0; i <= r; i++, j++) {
		a[i] = v[j];
	}
}

void merge_sort(int l, int r) {
	
	if(l == r) return;
	
	int mid = (l + r) >> 1;
	
	merge_sort(l, mid);
	merge_sort(mid + 1, r); 
	
	merge(l, mid, r);
	
}

int main() {
	
	cin>>n;
	for(int i = 1; i <= n; i++) {
		cin>>a[i];
	}
	
	merge_sort(1, n);
	for(int i = 1; i <= n; i++) cout<