【刷题-LeetCode】300. Longest Increasing Subsequence

1. Longest Increasing Subsequence

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 is 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?

解 动态规划[https://www.cnblogs.com/vinnson/p/10845125.html]

class Solution {
public:
    int lengthOfLIS(vector<int>& nums) {
        int n = nums.size();
        if(n == 0)return 0;
        int *dp = new int[n];
        for(int i = 0; i < n; ++i)dp[i] = 1;
        int ans = 1;
        for(int i = 1; i < n; ++i){
            for(int j = 0; j < i; ++j){
                if(nums[i] > nums[j])dp[i] = max(dp[i], dp[j]+1);
            }
            ans = max(ans, dp[i]);
        }
        delete []dp;
        return ans;
    }
};