Leetcode-300. Longest Increasing Subsequence
阿新 • • 發佈:2018-11-02
https://leetcode.com/problems/longest-increasing-subsequence/description/
Given an unsorted array of integers, find the length of longest increasing subsequence.
Example:
Input:[10,9,2,5,3,7,101,18]
Output: 4 Explanation: The longest increasing subsequence is[2,3,7,101]
, therefore the length is4
.
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?
題解:dag動態規劃模型,O(nlogn)沒想到,看討論是用二分搜尋。
class Solution { public: int lengthOfLIS(vector<int>& nums) { int l = nums.size(); if (l <= 1){ return l; } int ans = 1; vector<int> dp(l, 1); for (int i = 1; i < l; i++){ for (int j = 0; j < i; j++){ if (nums[j] < nums[i]){ dp[i] = max(dp[i], dp[j] + 1); } } ans = max(ans, dp[i]); } return ans; } };