温习归并排序

一.自己的代码

1.源码

#include<stdio.h>
#define N 100

void merge(int a[],int left,int right,int mid){
	int temp[N];
	int l_pos=left,r_pos=mid+1;
	int pos=left;
	while(l_pos<=mid&&r_pos<=right){
		if(a[l_pos]<a[r_pos]) temp[pos++]=a[l_pos++];
		else temp[pos++]=a[r_pos++];
	}
	while(l_pos<=mid) temp[pos++]=a[l_pos++];
	while(r_pos<=right) temp[pos++]=a[r_pos++];
	while(left<=right){
		a[left]=temp[left];
		left++;
	}
}

void mergeSort(int a[],int left,int right){
	if(left<right){
		int mid=(left+right)/2;
		mergeSort(a,left,mid);
		mergeSort(a,mid+1,right);
		merge(a,left,right,mid);
	}
} 

int main(){
	int a[N];
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
		scanf("%d",a+i);
	mergeSort(a,0,n-1);
	for(int i=0;i<n;i++)
		printf("%d ",a[i]);
}

2.测试

2.1测试数据

9
1 3 2 2 5 4 77 4 1

2.2结果

二.y总的模板

#include<iostream>

using namespace std;
const int N=100;

void mergeSort(int a[],int left,int right){
	if(left<right){
		int mid =(left+right)/2;
		mergeSort(a,left,mid);
		mergeSort(a,mid+1,right);
		int temp[N],l_pos=left,r_pos=mid+1,pos=left;
		while(l_pos<=mid&&r_pos<=right){
			if(a[l_pos]<a[r_pos]) temp[pos++]=a[l_pos++];
			else temp[pos++]=a[r_pos++];
		}
		while(l_pos<=mid) temp[pos++]=a[l_pos++];
		while(r_pos<=right) temp[pos++]=a[r_pos++];
		for(int i=left;i<=right;i++) a[i]=temp[i];
	}
}

int main(){
	int n;
	int a[N];
	scanf("%d",&n);
	for(int i=0;i<n;i++)
		scanf("%d",a+i);
	mergeSort(a,0,n-1);
	for(int i=0;i<n;i++)
		printf("%d ",a[i]);
	return 0;
}