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trie implementation?

kickstart problems

look in todos in tmp/cj# on mac

+ start several different compilations at once

normal -> sanitizer without LOCAL flag

add random and set headers

add stubs for gen functions before ‘main’

https://cstheory.wordpress.com/2008/03/07/superconcentrators-from-expanders/

implement simplier prime factorization list to frq map function https://cses.fi/book.html Techniques

  • Exchange elements - to sort the sequence

snackdown2019 elim https://codeforces.com/blog/entry/18051 https://ioinformatics.org/journal/v12_2018_25_41.pdf upsolve

Hacker’s Delight tooling

  • visualize graph from standard representations
  • update codeforces task parser to output to A.in / A.out or separate files
  • dcj compilation
  • restore layout after gdb session
  • test harness
    • random generators
    • interactive problems
    • colored passed / failed
    • create new test case
  • server for chelper
    • it will wait for chelper when received an input
      • save file to temporary directory
      • test override confirmation
      • write url and full name of problem in problem file
      • test under linux
      • parser
        • topcoder?
        • usaco
        • gcj
        • icpclive
  • open problem by url

debugger

дневники дейкстра #define local pre contest routine Petr’s post on BIT interval updates and queries proper implementation of interval tree force.py

  • list of opened problems
  • mark done of one of them
  • filter problems with tutorials

hacks on vacation

check 3rd solutions of

  • 10771 
  • codejam round 3

notes for CP3

  • chapter 3
    • p 92 why sort by right endpoint? How does it helps ?
    • problems
      • Recursive Backtracking (Harder) - 416 - it’s solvable by iteration through possible starts [0, 9] because we are looking for continuous sub-sequences only (like {7,6,5} but {7,6,4}). We can do it by backtracking too but that doesn’t look natural for me. I would classify it as “two loops” or “binary operations” problem.
      • Involving Sorting (Or The Input Is Already Sorted) - 12210 - A Match Making Problem: solution here is to find the difference (B-S) and minimum element in bachelor ages. We can go without any sorting / greedy here (+code)
      • 196 - Spreadsheet - does not look like DP for me. You just need to “invent” data structure to handle references and that’s all
      • 10465 - Homer Simpson - solvable by simple loop (+code)
  • chapter 4
    • p. 134 ure are using “visited” array to mark explored and non-explored vertices. It’s a bit confusing to read
      • if (dfs_num[x] == UNVISITED) …; if (visited[x]) ..
    • p. 187 answer to 4.2.5.2 (data structure wit O(1) insert front/back) what about deque?
    • p 189 4.5.3.1 -we can do the SCC search on undirected graph too
    • 10596 - problem has kinda weird test cases on OJ (i.e. when we check for connectivity we should only consider vertices that have edges and expecting to see at least one component) - for me problem has low dacu because of that.
  • chapter 5
    • p. 220 problem 11344 we can do with modulo arithmetic instead of remembering div trails
    • p 221 side note 15 “staying…” Is “winning”?
  • chapter 6
    • p. 262 it worth noting that sentinels could be the same (a$b$) but we should check for sentinel in LCP calculation. This is needed for example in 11107 - Life Forms problem when we have a lot of strings to cross-match
  • chapter 9
    • p. 381 listing - second call should be RandomizedSelect(A, q + 1, r, k - q)
  • visualization to max flow min cost?