归并排序模板

C++模板

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

    int mid = (l + r)/2;
    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]) tmp[k ++ ] = q[i ++ ];
        else tmp[k ++ ] = q[j ++ ];

    while (i <= mid) tmp[k ++ ] = q[i ++ ];
    while (j <= r) tmp[k ++ ] = q[j ++ ];

    for (i = l, j = 0; i <= r; i ++, j ++ ) q[i] = tmp[j];
}

C模板

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void merge_sort(int q[], int l, int r){
    int tmp[N];
    if(l >= r) return;
    int mid = (l+r)/2; 
    
    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]) tmp[k++] = q[i++];
        else tmp[k++] = q[j++];
    while(i <= mid) tmp[k++] = q[i++];
    while(j <= r) tmp[k++] = q[j++];
    
    for(i=l,j=0; i <= r;i++,j++) q[i]=tmp[j];
}

题目描述：

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∼109 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

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#include<iostream>

using namespace std;

const int N = 1e5+10;

int n;
int q[N], tmp[N];

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

    int mid = (l + r)/2;
    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]) tmp[k ++ ] = q[i ++ ];
        else tmp[k ++ ] = q[j ++ ];

    while (i <= mid) tmp[k ++ ] = q[i ++ ];
    while (j <= r) tmp[k ++ ] = q[j ++ ];

    for (i = l, j = 0; i <= r; i ++, j ++ ) q[i] = tmp[j];
}


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

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#include <stdio.h>

const int N = 1e6 + 10;

void merge_sort(int q[], int l, int r){
    int tmp[N];
    if(l >= r) return;
    int mid = (l+r)/2; 
    
    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]) tmp[k++] = q[i++];
        else tmp[k++] = q[j++];
    while(i <= mid) tmp[k++] = q[i++];
    while(j <= r) tmp[k++] = q[j++];
    
    for(i=l,j=0; i <= r;i++,j++) q[i]=tmp[j];
}

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