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  • leetcode 674. Longest Continuous Increasing Subsequence

    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.

    class Solution(object):
        def findLengthOfLCIS(self, nums):
            """
            :type nums: List[int]
            :rtype: int
            """
            if not nums: return 0
            ans = 1
            cnt = 1
            for i in xrange(1, len(nums)):
                if nums[i] > nums[i-1]:
                    cnt += 1
                    ans = max(ans, cnt)
                else:
                    cnt = 1
            return ans

    本质上还是计数器!发现没有递增就reset计数器。

    或者是用贪心也可以:

    class Solution(object):
        def findLengthOfLCIS(self, nums):
            """
            :type nums: List[int]
            :rtype: int
            """        
            ans = 0
            i = 0
            while i < len(nums):
                cnt = 1        
                while i+1<len(nums) and nums[i+1]>nums[i]:
                    i += 1
                    cnt += 1
                ans = max(ans, cnt)
                i += 1
            return ans

    还有dp解法,虽然看起来不是那么舒服:

    class Solution {
        public int findLengthOfLCIS(int[] nums) {
            if (nums == null || nums.length == 0) return 0;
            int n = nums.length;
            int[] dp = new int[n];
            
            int max = 1;
            dp[0] = 1;
            for (int i = 1; i < n; i++) {
                if (nums[i] > nums[i - 1]) {
                    dp[i] = dp[i - 1] + 1;
                }
                else {
                    dp[i] = 1;
                }
                max = Math.max(max, dp[i]);
            }
            
            return max;
        }
    }
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  • 原文地址:https://www.cnblogs.com/bonelee/p/8729132.html
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