Ways to Sum to N Using 1, 2 and 5
MediumP3Coding
Count the ways to write n as a sum of 1s, 2s and 5s where the order of the terms matters. For example n = 3 has 3 ways: 1+1+1, 1+2 and 2+1. Zero has one way (the empty sum).
Example 1
- Input
- n = 3
- Output
- 3
- Why
- 1+1+1, 1+2 and 2+1.
Example 2
- Input
- n = 1
- Output
- 1
Example 3
- Input
- n = 0
- Output
- 1
Constraints
- 0 <= n <= 60
- The answer fits in a 53-bit integer.
Hints
Give it a real attempt first. Run shows which examples fail.
Saved automatically
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