[LeetCode] 674. Longest Continuous Increasing Subsequence

Problem

Given an unsorted array of integers, find the length of longest continuous increasing subsequence (subarray).

Example 1:
Input: [1,3,5,4,7]
Output: 3
Explanation: The longest continuous increasing subsequence is [1,3,5], its length is 3.
Even though [1,3,5,7] is also an increasing subsequence, it`s not a continuous one where 5 and 7 are separated by 4.
Example 2:
Input: [2,2,2,2,2]
Output: 1
Explanation: The longest continuous increasing subsequence is [2], its length is 1.
Note: Length of the array will not exceed 10,000.

Solution #1 using index

class Solution {
    public int findLengthOfLCIS(int[] nums) {
        if (nums == null || nums.length == 0) return 0;
        int start = 0, max = 1, pre = nums[0];
        for (int i = 1; i < nums.length; i++) {
            if (nums[i] > pre) {
                pre = nums[i];
                max = Math.max(max, i-start+1);
            } else {
                pre = nums[i];
                start = i;
            }
        }
        return max;
    }
}

Solution #2 using count

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