数组实现二路归并排序

使用数组实现二路归并排序

#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
#include<list>
#include<queue>
using namespace std;

void merge(vector<int>&arr,int left1,int right1,int left2,int right2){
	int i=left1,j=left2;
	vector<int>res;
	while(i<=right1&&j<=right2){
		if(arr[i]<=arr[j]){
			res.push_back(arr[i]);
			i++;
		}
		else{
			res.push_back(arr[j]);
			j++;
		}
	}
	
	while(i<=right1){
			res.push_back(arr[i]);
			i++;
	}
	while(j<=right2){
			res.push_back(arr[j]);
			j++;		
	}
	j=0;
	for(i=left1;i<=right2;i++){
		arr[i]=res[j++];
	}
	return;
}
void merge_sort(vector<int>&arr,int left,int right){
	if(left>=right)
	     return;
	merge_sort(arr,left,left+(right-left)/2);
	merge_sort(arr,left+(right-left)/2+1,right);
	merge(arr,left,left+(right-left)/2,left+(right-left)/2+1,right);
	return;
}
int main(){
   vector<int>arr;
   int n;
   cin>>n;
   while(n--){
   	int tmp;
   	cin>>tmp;
   	arr.push_back(tmp);
   }
  merge_sort(arr,0,arr.size()-1);
  for(int tmp:arr){
  	cout<<tmp<<" ";
  }
}