折半插入排序（Binary Insert Sort）

int low=0,mid,high=n-1;
while(low<=high){
   mid = (low+high)/2;
    if(x<a[mid])
          high = mid - 1;
     else

         low = mid+1;

}

for(i=n-1;i>=low;i--)

     a[i+1] = a[i];

a[low] = x;