折半插入排序

#include <iostream>
using namespace std;
int main()
{
    const int MAXN = 100;
    int a[MAXN];
    int n;
    cin >> n;
    int i, j;
    int low, high, mid;
    for(i = 1; i <= n; i++)
    {
        cin >> a[i];
    }
    int tmp;
    for(i = 2; i <= n; i++)
    {
        tmp = a[i];
        low = 1;
        high = i-1;
        while(low <= high)
        {
            mid = (low + high) / 2;
            if(a[mid] < a[i])
                low = mid + 1;
            else
                high = mid - 1;
        }
        for(j = i-1; j >= low; j--)
            a[j+1] = a[j];
        a[low] = tmp;
    }
    for(i = 1; i <= n; i++)
        cout << a[i] << " ";
    return 0;
}

虽然时间上仍为O(n^2)，但是提高了查找插入位置的效率。

来自为知笔记(Wiz)