logseq_notes/journals/2023_04_07.md

• DONE Ardour
  • 怎么录制
  • Ardour vs. audacity
• Leetcode - Happy Number collapsed:: true
  • Times:
    • Time when completed: 12:36
    • Time taken to complete: I forgot, very quick I suppose
    • Revisions:
  • Tags:
    • Algorithms: #Floyd_s_cycle_finding_algorithm
    • Difficulty: #difficulty_easy
    • Platforms: #leetcode
  • Links:
    • link to the problem
  • Problem:

    • Write an algorithm to determine if a number n is happy.

      A happy number is a number defined by the following process:

      • Starting with any positive integer, replace the number by the sum of the squares of its digits.
      • Repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.

    • Those numbers for which this process ends in 1 are happy.

      Return true if n is a happy number, and false if not.

  • Examples:

    • Example 1:
      
      Input: n = 19
      Output: true
      Explanation:
      12 + 92 = 82
      82 + 22 = 68
      62 + 82 = 100
      12 + 02 + 02 = 1
      
      Example 2:
      
      Input: n = 2
      Output: false
      
      

  • Constraints:
    • 1 <= n <= 231 - 1
  • Thoughts:
    • Intuition:
      • It loops endlessly in a cycle, which means we need to use a cycle detection algorithm, which happens to be the Floyd's Cycle Finding Algorithm.
    • Approach:
      • Use the Floyd's cycle finding algorithm, with two variables
      • when fast == slow, cycle is found
      • detect if fast is 1, and return values
  • Solution:
    • Code

      • class Solution {
          private int progress(int n) {
            int sum = 0;
            while (n > 0) {
              sum += (n % 10) * (n % 10);
              n /= 10;
            }
            return sum;
          }
          public boolean isHappy(int n) {
            // loop detection
            int slow = progress(n);
            int fast = progress(slow);
        
            while (slow != fast) {
              slow = progress(slow);
              fast = progress(progress(fast));
            }
        
            return (fast == 1);
          }
        }
        

• Daily reflection Daily reflections collapsed:: true
  • What I've done
    • 写学交论文
    • 音乐 improvising
    • I met someone, she's gorgeous
  • What I've thought #thoughts
    • Improvisation is fun :)
    • I think I fall in love with someone, I have a strong feeling when she is nearby, and dopamine burst out whenever I talk to her. I don't know if she feel the same (I think to some extent she does. I don't really know, I just follow the flow and enjoy every moment of that). aaand also I erected a lot
  • Mood
    • Generally excited, but sometimes exhausted from these happy feelings, I deserve a good sleep.
• Todo
  • DONE Edx 写一篇 blues :LOGBOOK: CLOCK: [2023-04-07 Fri 14:36:18]--[2023-04-07 Fri 16:50:36] => 02:14:18 :END:
  • DONE 概率论作业 :LOGBOOK: CLOCK: [2023-04-07 Fri 17:31:14]--[2023-04-07 Fri 21:19:06] => 03:47:52 :END:
    • DONE 22, 23, 24, 25, 26, 27, 29
    • DONE 58, 59
• 乐理学习 #music
  • LATER 每天学 15 分钟 Open Music Theory 上次学到的地方 SCHEDULED: <2023-05-16 Tue .+1d> :LOGBOOK:
    • State "DONE" from "LATER" [2023-04-07 Fri 16:50]
    • State "DONE" from "LATER" [2023-04-07 Fri 16:52]
    • State "DONE" from "LATER" [2023-04-10 Mon 22:49]
    • State "DONE" from "LATER" [2023-04-11 Tue 23:35] CLOCK: [2023-04-12 Wed 09:16:56]--[2023-04-12 Wed 09:44:02] => 00:27:06
    • State "DONE" from "LATER" [2023-04-12 Wed 09:44]
    • State "DONE" from "LATER" [2023-04-18 Tue 23:31]
    • State "DONE" from "LATER" [2023-04-21 Fri 09:30] CLOCK: [2023-04-23 Sun 15:18:42]--[2023-04-23 Sun 15:18:43] => 00:00:01
    • State "DONE" from "NOW" [2023-04-23 Sun 15:18]
    • State "DONE" from "LATER" [2023-04-26 Wed 22:31]
    • State "DONE" from "LATER" [2023-05-08 Mon 20:47] CLOCK: [2023-05-09 Tue 09:52:58]--[2023-05-09 Tue 10:01:36] => 00:08:38
    • State "DONE" from "NOW" [2023-05-09 Tue 10:01] CLOCK: [2023-05-09 Tue 10:11:30]--[2023-05-09 Tue 10:11:31] => 00:00:01 CLOCK: [2023-05-11 Thu 10:14:15]--[2023-05-11 Thu 11:16:14] => 01:01:59
    • State "DONE" from "NOW" [2023-05-11 Thu 11:16]
    • State "DONE" from "LATER" [2023-05-15 Mon 16:23] :END:
  • LATER 每天 5 分钟 Ear training Teoria SCHEDULED: <2023-05-12 Fri .+1d> :LOGBOOK:
    • State "DONE" from "LATER" [2023-04-07 Fri 23:31]
    • State "DONE" from "LATER" [2023-04-11 Tue 16:41]
    • State "DONE" from "LATER" [2023-04-12 Wed 15:07] CLOCK: [2023-04-21 Fri 14:41:07]--[2023-04-21 Fri 14:41:09] => 00:00:02
    • State "DONE" from "LATER" [2023-04-25 Tue 11:33]
    • State "DONE" from "LATER" [2023-04-26 Wed 22:31]
    • State "DONE" from "LATER" [2023-05-08 Mon 20:48] CLOCK: [2023-05-09 Tue 10:01:48]--[2023-05-09 Tue 10:10:01] => 00:08:13
    • State "DONE" from "LATER" [2023-05-09 Tue 10:10]
    • State "DONE" from "LATER" [2023-05-11 Thu 20:06] :END: