Given an unsorted array of integers,find the length of longest increasing subsequence.
Example:
Input: Output: 4 Explanation: The longest increasing subsequence is,therefore the length is . [10,9,2,5,3,7,101,18][2,101]4
Note:
- There may be more than one LIS combination,it is only necessary for you to return the length.
- Your algorithm should run in O(n2) complexity.
Follow up: Could you improve it to O(n log n) time complexity?
O(n^2): dp
class Solution { public: int lengthOfLIS(vector<int>& nums) { int n = nums.size(); vector<int> dp(n,1); int res = 0; for (int i = 0; i < n; ++i) { for (int j = 0; j < i; ++j) { if (nums[j] < nums[i]) dp[i] = max(dp[i],dp[j]+1); } res = max(res,dp[i]); } return res; } };