Subtracting

Length (1-Based) - index (0-Based)

• The length and number of elements from the index (one side inclusive) to the end.

Example:

data = ['T', 'A', 'I', 'P', 'E', 'I']

If we take the length (6) and subtract index 2 ('I'): 6 - 2 = 4

This result, 4, means:

• The length and number of letters from the index (one side inclusive) is 4.

Two 0-Based Indices (Larger - Smaller)

• It’s the number of “gaps” or “steps” between two indices.
• It’s also the number of elements (one side inclusive) between the indices
  • length - 1
  • (gaps + 1) - 1
  • (larger_idx - smaller_ids + 1) - 1
  • larger_idx - smaller_ids
• The length and number of elements (both inclusive) between the indices is gaps + 1.
• The number of elements (both exclusive) between the indices
  • length - 2
  • (gaps + 1) - 2
  • (larger_idx - smaller_ids + 1) - 2
  • larger_idx - smaller_ids - 1
  • ⭐️⭐️ (Hard) 84. Largest Rectangle in Histogram, NeetCode 150

Example

data = ['T', 'A', 'I', 'P', 'E', 'I']

If we subtract index 1 ('A') from index 4 ('E'): 4 - 1 = 3

This result, 3, means:

• It has 3 gaps (steps) from index 1 ('A') to index 4 ('E').
• The length and number of letters between them is 3 + 1.

Kth (1-Index-Based)