Given an unsorted array of integers, find the length of longest increasing subsequence.

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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.

LIS，大名鼎鼎，初级dp

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class Solution {
    public int lengthOfLIS(int[] nums) {
        int n = nums.length;
        if (n == 0) return 0;
        int[] f = new int[n];
        Arrays.fill(f, 1);
        
        int res = 0;
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < i; ++j) {
                if (nums[i] > nums[j]) {
                    f[i] = Math.max(f[i], f[j] + 1);
                }        
            }
            res = Math.max(res, f[i]);
        }
        return res;
    }
}

O(n log n)方法: 还没写