Skip to content

Prepare For Coder Interview – Denny

  • Basic
  • Medium
  • Hard
  • Architect
  • Life

LeetCode: Number of Longest Increasing Subsequence

Posted on June 18, 2019July 26, 2020 by braindenny

Number of Longest Increasing Subsequence



Similar Problems:

  • CheatSheet: Leetcode For Code Interview
  • CheatSheet: Common Code Problems & Follow-ups
  • Tag: #lis

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

Example 1:

Input: [1,3,5,4,7]
Output: 2
Explanation: The two longest increasing subsequence are [1, 3, 4, 7] and [1, 3, 5, 7].

Example 2:

Input: [2,2,2,2,2]
Output: 5
Explanation: The length of longest continuous increasing subsequence is 1, and there are 5 subsequences' length is 1, so output 5.
Note: Length of the given array will be not exceed 2000 and the answer is guaranteed to be fit in 32-bit signed int.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.


  • Solution:
// https://code.dennyzhang.com/number-of-longest-increasing-subsequence
// Basic Ideas: dynamic programming
//    dp(i): ends with nums[i]
// Complexity: Time O(n*n), Space O(n)
type Node struct {
    max int
    count int
}
func findNumberOfLIS(nums []int) int {
    res, max := 0, 0
    l := make([]Node, len(nums))
    for i, num := range nums {
        l[i].max, l[i].count = 1, 1
        if i != 0 {
            for j:=i-1; j>=0; j-- {
                if nums[j] < num {
                    if l[j].max+1 > l[i].max {
                        l[i].max, l[i].count = l[j].max+1, l[j].count
                    } else {
                        if l[j].max+1 == l[i].max {
                            l[i].count += l[j].count
                        }
                    }
                }
            }
        }
        if l[i].max > max { 
            max, res = l[i].max, l[i].count
        } else {
            if l[i].max == max {
                res += l[i].count
            }
        }
    }
    return res
}
linkedin
github
slack

Post Views: 0
Posted in BasicTagged lis, redo

Post navigation

LeetCode: Insufficient Nodes in Root to Leaf Paths
LeetCode: Delete Columns to Make Sorted II

Leave a Reply Cancel reply

Your email address will not be published.

Tags

#array #backtracking #bfs #binarytree #bitmanipulation #blog #classic #codetemplate #combination #dfs #dynamicprogramming #game #graph #greedy #heap #inspiring #interval #linkedlist #manydetails #math #palindrome #recursive #slidingwindow #stack #string #subarray #trie #twopointer #twosum binarysearch editdistance hashmap intervaldp knapsack monotone oodesign presum rectangle redo review rotatelist series sql treetraversal unionfind

Recent Posts

  • a
  • a
  • a
  • a
  • a

Recent Comments

    Archives

    Categories

    • Amusing
    • Basic
    • Easy
    • Hard
    • Life
    • Medium
    • Resource
    • Review
    • Series
    • Uncategorized
    Proudly powered by WordPress | Theme: petals by Aurorum.