nlog(n)解动态规划--最长上升子序列(Longest increasing subsequence)

#include <iostream>

using namespace std;

int LIS_nlogn(int *arr, int len)
{
    int *LIS = new int[len];    //LIS[i]存储的是每个最长长度i的最小结尾,即在arr里的最小结尾
    for (int i = 0; i < len; i++)
    {
        LIS[i] = -1;
    }

    int maxLen = 1;    //记录最长上升子串的最大长度
    LIS[0] = arr[0];

    for (int i = 0; i < len; ++i)
    {
        int low = 0, high = maxLen, mid;
        while (low <= high)
        {
            mid = (low + high)/2;
            if (LIS[mid] < arr[i])
            {
                low = mid + 1;
            } 
            else
            {
                high = mid - 1;
            }
        }
        LIS[low] = arr[i];    //插入元素到相应的位置
        if (low > maxLen)
        {
            maxLen++;
        }
    }

    delete LIS;

    return maxLen;
}

int main()
{

    int arr[] = {2,1,5,3,6,4,8,9,7};
    int len = 9;
    int ret;

    ret = LIS_nlogn(arr, len);

    cout<<ret<<endl;

    return 0;
}