368. 最大整除子集

LeetCode每日一题 2021/4/23

class Solution{
public:
	vector<int> largestDivisibleSubset(vector<int> &nums){
		int len = nums.size();
		if(len < 2) return nums;
		sort(nums.begin(), nums.end());
		vector<int> dp(len, 1);
		vector<int> path(len, -1);
		int maxIndex = -1, maxLen = 0;
		for(int i = 0; i < len; i++){
			for(int j = 0; j < i; j++){
				if(nums[i] % nums[j] == 0){
					if(dp[i] < dp[j] + 1){
						dp[i] = dp[j] + 1;
						path[i] = j;
					}
				}
			}
			if(dp[i] > maxLen){
				maxLen = dp[i];
				maxIndex = i;
			}
		}
		int index = maxIndex;
		vector<int> ans;
		while(index != -1){
			ans.push_back(nums[index]);
			index = path[index];
		}
		return ans;
	}
};

//解法2
class Solution{
public:
	vector<int> largestDivisibleSubset(vector<int> &nums){
		int len = nums.size();
		if(len < 2) return nums;
		sort(nums.begin(), nums.end());
		using PII = pair<int, int>;
		PII dp[n];
		for(int i = 0; i < len; i++){
			PII rec(1, i);
			for(int j = 0; j < i; j++){
				if(nums[i] % nums[j] == 0 && dp[j].first + 1 > rec.first){
					rec = {dp[j].first + 1, j};
				}
			}
			dp[i] = rec;
		}
		int idx = max_element(dp, dp + len) - dp;
		int val = dp[idx].first;
		vector<int> ans;
		while(val--){
			ans.push_back(nums[idx]);
			idx = dp[idx].second;
		}
		return ans;
	}
};