Given an array A of positive lengths, return the largest perimeter of a triangle with non-zero area, formed from 3 of these lengths.
If it is impossible to form any triangle of non-zero area, return 0.
Example 1:
Input: [2,1,2] Output: 5 Example 2:
Input: [1,2,1] Output: 0 Example 3:
Input: [3,2,3,4] Output: 10 Example 4:
Input: [3,6,2,3] Output: 8
Note:
3 <= A.length <= 10000 1 <= A[i] <= 10^6
public class Solution {
public int LargestPerimeter(int[] A) {
Array.Sort(A);
for(int i=A.Length-1;i>1;i--){
if(A[i]<A[i-1]+A[i-2]){
return A[i]+A[i-1]+A[i-2];
}
}
return 0;
}
}Time Complexity: O(nlogn)
Space Complexity: O(1)
