$$\color{Red}{归并排序-三种语言代码}$$

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题目介绍

给定你一个长度为 n 的整数数列。

请你使用归并排序对这个数列按照从小到大进行排序。

并将排好序的数列按顺序输出。

输入格式

输入共两行，第一行包含整数 n。

第二行包含 n 个整数（所有整数均在 1 ∼ 10 ^ 9 范围内），表示整个数列。

输出格式

输出共一行，包含 n 个整数，表示排好序的数列

数据范围

1 ≤ n ≤ 100000

输入样例：

5
3 1 2 4 5

输出样例：

1 2 3 4 5

java 解法

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    static int N = 100010, n;
    static int[] a = new int[N];
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    static void merge_sort(int l, int r, int[] a) {
        if (l >= r) return;
        int mid = l + r >> 1;
        merge_sort(l, mid, a);
        merge_sort(mid + 1, r, a);
        int [] back = new int[r - l + 1];
        int i = l, j = mid+1, k = 0;
        while (i <= mid && j <= r){
            if (a[i] <= a[j]) back[k++] = a[i++];
            else back[k++] = a[j++];
        }
        while (i <= mid) back[k++] = a[i++];
        while (j <= r) back[k++] = a[j++];
        i = l;
        j = 0;
        while (i <= r) a[i++] = back[j++];
    }

    public static void main(String[] args) throws IOException {
        n = Integer.parseInt(br.readLine());
        String [] s = br.readLine().split(" ");
        for (int i = 0; i < n; i++) a[i] = Integer.parseInt(s[i]);
        merge_sort(0, n-1, a);
        for (int i = 0; i < n; i++) System.out.print(a[i] + " ");
    }
}

C++ 解法

#include<iostream>
using namespace std;

int n;
const int N = 100000;
int q[N], tem[N];

void merge_sort(int q[], int l, int r)
{
    if (l >= r) return;
    int mid = l + r >> 1;

    merge_sort(q, l, mid), merge_sort(q, mid + 1, r);
    int k = 0, i = l, j = mid + 1;
    while(i <= mid && j <= r)
    {
        if(q[i] <= q[j])    tem[k++] = q[i++];
        else    tem[k++] = q[j++];
    }

    while(i <= mid) tem[k++] = q[i++];
    while(j <= r)   tem[k++] = q[j++];
    k = 0;
    while(l <= r)   q[l++] = tem[k++];
}

int main()
{
    scanf("%d", &n);
    for(int i=0; i<n; i++)  cin >> q[i];

    merge_sort(q, 0, n-1);

    for(int i=0; i<n; i++) cout << q[i] << ' ';

    return 0;
}

python3 解法

def merge_sort(q, l, r):
    if l >= r:
        return
    mid = (l + r) // 2
    merge_sort(q, l, mid), merge_sort(q, mid+1, r)
    i, j = l, mid + 1
    tem = []
    while i <= mid and j <= r:
        if q[i] <= q[j]:
            tem.append(q[i])
            i += 1
        else:
            tem.append(q[j])
            j += 1
    while i <= mid:
        tem.append(q[i])
        i += 1
    while j <= r:
        tem.append(q[j])
        j += 1
    q[l:r+1] = tem

if __name__ == '__main__':
    n = int(input())
    q = [int(x) for x in input().split()]
    merge_sort(q, 0, n-1)
    for i in q:
        print(i, end=' ')