PRACTICES

We typically run training session once a week. You can join us to track upcoming events.

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WANT TO GET STARTED?!

If you want to jump in and try a few problems on your own, here are a couple websites that host some problems. If you have any questions or problems, please contact me and I will help you out in any way that I can!

1. Input/Output

Being familiar with IO is the first step, there are some common patterns on dealing with IO.

• Input/output: py, cpp

  Python3

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  # read two ints
  a, b = map(int, input().strip().split())
  
  # read a list of ints
  arr = list(map(int, input().strip().split()))
  

• Input/output: cpp only

  cpp

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  // read two ints
  scanf("%d%d", &a, &b);
    
  // or
  cin >> a >> b
  
  // read a series of ints
  while (scanf("%d", &a) != EOF) {
    // do some thing
  }
  
  // or
  while (cin >> a) {
    // do some thing
  }
  

2. Analyze your program

Pay attention to Time limit, Memory limit constraints in your problem statement when you get Time Limit Exceeded (TLE) or Memory Limit Exceeded (MLE) verticts.

C++ can nearly run $10^8$ basic operations (e.g. +, -) in 1 second; while Python can nearly run $10^6$ basic operations in 1 second. You can estimate your program running time based on these info and your complexity analysis to avoid TLE and MLE.

3. Try some algorithmic problems

It’s time to be involved in some problem-solving skill

• Looping and binary-searching

  Binary search

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  # my favorite pattern 
  best = None
  while l <= r:         # search space is [l, r]
    m = (l + r) // 2    # choose middle
    if check(m) :       # is m >=  
                        # invariant: all v in [l, r] >=
      l = m + 1         # shrink search space 
      best = m          # best so far
    else:
      r = m - 1         # shrink search space
  return best
  

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