368. Largest Divisible Subset

Given a set of distinct positive integers, find the largest subset such that every pair (S_i, S_j) of elements in this subset satisfies: S_i % S_j = 0 or S_j % S_i = 0.

If there are multiple solutions, return any subset is fine.

Example 1:

nums: [1,2,3]Result: [1,2] (of course, [1,3] will also be ok)

Example 2:

nums: [1,2,4,8]Result: [1,2,4,8]

这题是一道动态规划题，先对数组排序，然后dp，利用一个二维数组，每一个数对应自己当前的整除数列，先遍历数组，然后对从当前数一直减到0的数遍历，找到一个当前数能整除的数，那么说明当前数可以放在以j为末尾的整除数列后，一直找到最长的j的整除数列，就可以得到最长的以i为结尾的整除数列，于是最后就可以得到整个字符串的最长的整除数列，具体代码如下：

class Solution {public:    vector<int> largestDivisibleSubset(vector<int>& nums)     {        sort(nums.begin(),nums.end());        vector<vector<int> > f(nums.size());        vector<int> anw;        for(int i=0;i<nums.size();i++)        {            for(int j=i;j>=0;j--)            {                if(nums[i]%nums[j]==0&&f[j].size()>f[i].size())                {                    f[i]=f[j];                }                            }            f[i].push_back(nums[i]);            if(anw.size()<f[i].size())            anw=f[i];        }        return anw;    }};