703475. Maximum Perimeter of Triangle from array
Maximum Perimeter of Triangle from array
Summary
Given an array of integers, find the maximum perimeter that can be obtained by forming triangles using three consecutive elements from the array. For example, if the input array is [3, 5, 4], the maximum perimeter possible is 6 + 8 = 14 (using elements at indices 0, 1, and 2).
Detailed Explanation
To solve this problem, we can iterate over the array and for each triplet of consecutive elements, calculate the perimeter using the formula perimeter = a + b + c, where a, b, and c are the three consecutive elements. We keep track of the maximum perimeter found so far.
Here's a step-by-step breakdown:
- Initialize the maximum perimeter to 0.
- Iterate over the array, considering each triplet of consecutive elements (i.e., elements at indices
i,i+1, andi+2). - Calculate the perimeter for the current triplet using
perimeter = a + b + c. - Update the maximum perimeter if the calculated perimeter is greater than the current maximum.
- Return the maximum perimeter found.
Time complexity: O(n), where n is the length of the input array, since we iterate over the array once. Space complexity: O(1), since we only use a constant amount of space to store the maximum perimeter and other variables.
Optimized Solutions
Java
public int maxPerimeter(int[] arr) {
int maxPerimeter = 0;
for (int i = 0; i < arr.length - 2; i++) {
int a = arr[i];
int b = arr[i+1];
int c = arr[i+2];
int perimeter = a + b + c;
if (perimeter > maxPerimeter) {
maxPerimeter = perimeter;
}
}
return maxPerimeter;
}