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1018. Largest Perimeter Triangle

Array Math Greedy Sorting

Problem - Largest Perimeter Triangle

Easy

Given an integer array nums, return the largest perimeter of a triangle with a non-zero area, formed from three of these lengths. If it is impossible to form any triangle of a non-zero area, return 0.

 

Example 1:

Input: nums = [2,1,2]
Output: 5
Explanation: You can form a triangle with three side lengths: 1, 2, and 2.

Example 2:

Input: nums = [1,2,1,10]
Output: 0
Explanation: 
You cannot use the side lengths 1, 1, and 2 to form a triangle.
You cannot use the side lengths 1, 1, and 10 to form a triangle.
You cannot use the side lengths 1, 2, and 10 to form a triangle.
As we cannot use any three side lengths to form a triangle of non-zero area, we return 0.

 

Constraints:

  • 3 <= nums.length <= 104
  • 1 <= nums[i] <= 106

Solutions

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class Solution:
    def largestPerimeter(self, nums: List[int]) -> int:
        nums.sort()
        for i in range(len(nums) - 1, 1, -1):
            if (test := nums[i - 1] + nums[i - 2]) > nums[i]:
                return test + nums[i]
        return 0

Submission Stats:

  • Runtime: 11 ms (81.88%)
  • Memory: 18.8 MB (45.57%)