排序：折半插入排序（时间复杂度 O(nlog2 n) ）

#include <math.h>
#include <string.h>
#include <stdio.h>
#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

//折半插入排序
void B_insertsort(int a[], int n)
{
    int i, j;
    int mid, low, high;

    for(i=2; i<=n; i++)
    {
        a[0]=a[i];
        low=1; high=i-1;
        while(low <= high)
        {
            mid = (low+high)/2;
            if(a[0]>a[mid])  // 此语句将决定是“由大到小” 还是 “由小到大”排序的顺序！
                low=mid+1;
            else
                high=mid-1;
        }
        for(j=i-1; j>=high+1; j--)
        {
            a[j+1]=a[j];
        }
        a[high+1]=a[0];
    }
}

int main()
{
    int a[200];
    int i, j;
    int n;
    while(~scanf("%d", &n))
    {
        for(i=1; i<=n; i++)
        {
            cin>>a[i];
        }
        B_insertsort(a, n);

        for(j=1; j<=n; j++)
        {
            if(j==1)
                cout<<a[j];
            else
                cout<<" "<<a[j];
        }
        cout<<endl;
    }
    return 0;
}