Sequence indexing [ref]
Problem
- Read the first and last values of
[10, 20, 30, 40].
- Read the second-to-last character of
"python".
- Read row
1, column 2 of [[1, 2, 3], [4, 5, 6]].
- Replace index
1 of [10, 20, 30] with 99.
- Read the left and right children of index
2 in a zero-based array heap.
Python solution
nums = [10, 20, 30, 40]
(nums[0], nums[-1]) # (10, 40)
"python"[-2] # 'o'
matrix = [[1, 2, 3], [4, 5, 6]]
matrix[1][2] # 6
nums = [10, 20, 30]
nums[1] = 99
nums # [10, 99, 30]
i = 2
(2 * i + 1, 2 * i + 2) # (5, 6)
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