Choose Three Lengths with the Largest Nondegenerate Triangle Perimeter

### Problem Choose three occurrences from `nums` as side lengths. Return the largest possible perimeter of a triangle with positive area, or0 if no such triangle exists. ```cpp class Solution { public: int largestPerimeter(vector<int>& nums); }; ``` ### Examples **Example 1:** ```text Input: nums = [4,5,9,10] Output: 24 Explanation: Sides5,9,10 satisfy5+9>10 and give the maximum perimeter24. ``` **Example 2:** ```text Input: nums = [1,2,3] Output: 0 Explanation: The only triple has1+2=3, so its area would be zero. ``` ### Constraints - `3 <= nums.length <= 10^4`. - `1 <= nums[i] <= 10^6`. ### Contract considerations Positive area excludes a degenerate straight-line triple. The output is the perimeter, not the side array. ```hint Read the boundary condition For a fixed largest side, only the two largest available smaller positions can maximize its chance of forming a triangle. ``` ### Boundary reminders Positive area excludes a degenerate straight-line triple. The output is the perimeter, not the side array.