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Problem solution · Python

Minimum Money Required Before Transactions

Minimum Money Required Before Transactions: a Python solution using direct simulation. Learn the idea, check the complexity, and read the full code, with credit to walkccc LeetCode Solutions.

Technique
Direct simulation
Source
walkccc LeetCode Solutions
Length
23 lines
Start with the idea.

Try the problem first. If you get stuck, read the approach below, then write your own solution. The full code is at the bottom.

Approach

Direct simulation

For Minimum Money Required Before Transactions, the implementation follows the problem’s operations directly while maintaining only the state needed for the next decision.

  1. Translate each rule into one explicit state update.
  2. Maintain the invariant after every processed item.
  3. Return the accumulated state once all relevant input has been handled.

Code notes

  • 23 lines of Python from the credited upstream file 2412.py.
  • The implementation visibly relies on sequence storage.
  • No explicit loop blocks detected.

Complexity

Count the number and nesting of passes over the input, then include the maintained containers in the memory estimate.

Check the problem constraints before deciding whether this complexity will pass.

Source

Code and credit

This code comes from walkccc LeetCode Solutions by P.-Y. Chen (walkccc) and is used under the MIT licence.

Open problem ↗Original source ↗
Full codeMinimum Money Required Before Transactions · PythonPython
Use this to learn the idea, then write your own version.
class Solution:  def minimumMoney(self, transactions: list[list[int]]) -> int:    ans = 0    losses = 0     # Before picking the final transaction, perform any transaction that raises    # the required money.    for cost, cashback in transactions:      losses += max(0, cost - cashback)     # Now, pick a transaction to be the final one.    for cost, cashback in transactions:      if cost > cashback:        # The losses except this transaction: losses - (cost - cashback), so        # add the cost of this transaction = losses - (cost - cashback) + cost.        ans = max(ans, losses + cashback)      else:        # The losses except this transaction: losses, so add the cost of this        # transaction = losses + cost.        ans = max(ans, losses + cost)     return ans

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