300. Longest Increasing Subsequence

class Solution {
    public int lengthOfLIS(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        }
        int[] lengthOfLIS = new int[nums.length];
        lengthOfLIS[0] = 1;
        int globalMax = lengthOfLIS[0];
        for (int i = 1; i < nums.length; i++) {
            lengthOfLIS[i] = 1;
            for (int j = i - 1; j >= 0; j--) {
                if (nums[j] < nums[i]) {
                    lengthOfLIS[i] = Math.max(lengthOfLIS[i], lengthOfLIS[j] + 1);
                    globalMax = Math.max(globalMax, lengthOfLIS[i]);
                }
            }
        }
        return globalMax;
    }
}

class Solution {
    public int lengthOfLIS(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        }
        int res = 0;
        int[] visited = new int[nums.length];
        for (int i = 0; i < nums.length; i++) {
            res = Math.max(res, lengthOfLIS(nums, i, visited));
        }
        return res;
    }
    private int lengthOfLIS(int[] nums, int pos, int[] visited) {
        if (pos == 0) {
            return 1;
        }
        if (visited[pos] > 0) {
            return visited[pos];
        }
        int res = 1;
        for (int i = 0; i < pos; i++) {
            if (nums[i] < nums[pos]) {
                res = Math.max(res, lengthOfLIS(nums, i, visited) + 1);
            }
        }
        visited[pos] = res;
        return visited[pos];
    }
}