Abbreviating the Product of a Range — LeetCode 2117 Python Solution
HardMath
- Problem
- #2117
- Pattern
- Math and Number Theory
- Reading time
- 5 min
- Source
- leetcode.com
The problem
You are given two positive integers left and right with left <= right. Calculate the product of all integers in the inclusive range [left, right].
Example
- Input
- left = 1, right = 4
- Output
- "24e0"
- Explanation
- The product is 1 × 2 × 3 × 4 = 24.
Python solution
Python
class Solution:
def abbreviateProduct(self, left: int, right: int) -> str:
cnt2 = cnt5 = 0
for x in range(left, right + 1):
while x % 2 == 0:
cnt2 += 1
x //= 2
while x % 5 == 0:
cnt5 += 1
x //= 5
c = cnt2 = cnt5 = min(cnt2, cnt5)
pre = suf = 1
gt = False
for x in range(left, right + 1):
suf *= x
while cnt2 and suf % 2 == 0:
suf //= 2
cnt2 -= 1
while cnt5 and suf % 5 == 0:
suf //= 5
cnt5 -= 1
if suf >= 1e10:
gt = True
suf %= int(1e10)
pre *= x
while pre > 1e5:
pre /= 10
if gt:
return str(int(pre)) + "..." + str(suf % int(1e5)).zfill(5) + "e" + str(c)
return str(suf) + "e" + str(c)Complexity
| Measure | Complexity |
|---|---|
| Time | O(n) or O(1) |
| Space | O(1) auxiliary |
Pattern: Math and Number Theory
Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 2117. Abbreviating the Product of a Range is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.
The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 2117. Abbreviating the Product of a Range?
- LeetCode 2117. Abbreviating the Product of a Range is rated Hard on LeetCode.
- What topics does LeetCode 2117. Abbreviating the Product of a Range cover?
- LeetCode 2117. Abbreviating the Product of a Range is tagged Math on LeetCode.