1018. Largest Perimeter Triangle¶

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1018. 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

Solution¶

class Solution {
    public int largestPerimeter(int[] nums) {
        int n = nums.length;
        Arrays.sort(nums);
        int ans = 0;
        for (int i = 0; i < n - 2; i++) {
            int x = nums[i], y = nums[i + 1], z = nums[i + 2];
            if (x + y > z && x + z > y && y + z > x)
                ans = Math.max(ans, x + y + z);
        }
        return ans;
    }
}

Complexity Analysis¶

• Time Complexity: O(?)
• Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here