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| 1 | +--- |
| 2 | +id: type-of-triangle |
| 3 | +title: Type of Triangle (LeetCode) |
| 4 | +sidebar_label: 3024-TypeOfTriangle |
| 5 | +tags: |
| 6 | + - Triangle |
| 7 | + - Array |
| 8 | +description: Determine the type of triangle that can be formed by an array of integers representing the sides of the triangle. |
| 9 | +sidebar_position: 3024 |
| 10 | +--- |
| 11 | + |
| 12 | +## Problem Description |
| 13 | + |
| 14 | +| Problem Statement | Solution Link | LeetCode Profile | |
| 15 | +| :---------------- | :------------ | :--------------- | |
| 16 | +| [Type of Triangle](https://leetcode.com/problems/type-of-triangle/) | [Type of Triangle Solution on LeetCode](https://leetcode.com/problems/type-of-triangle/solutions/) | [vaishu_1904](https://leetcode.com/u/vaishu_1904/) | |
| 17 | + |
| 18 | +## Problem Description |
| 19 | + |
| 20 | +You are given a 0-indexed integer array nums of size 3 which can form the sides of a triangle. |
| 21 | + |
| 22 | +A triangle is called equilateral if it has all sides of equal length. |
| 23 | +A triangle is called isosceles if it has exactly two sides of equal length. |
| 24 | +A triangle is called scalene if all its sides are of different lengths. |
| 25 | +Return a string representing the type of triangle that can be formed or "none" if it cannot form a triangle. |
| 26 | + |
| 27 | +### Example 1 |
| 28 | + |
| 29 | +- **Input:** `nums = [3,3,3]` |
| 30 | +- **Output:** `"equilateral"` |
| 31 | +- **Explanation:** Since all the sides are of equal length, therefore, it will form an equilateral triangle. |
| 32 | + |
| 33 | +### Example 2 |
| 34 | + |
| 35 | +- **Input:** `nums = [3,4,5]` |
| 36 | +- **Output:** `"scalene"` |
| 37 | +- **Explanation:** |
| 38 | + - `nums[0] + nums[1] = 3 + 4 = 7`, which is greater than `nums[2] = 5`. |
| 39 | + - `nums[0] + nums[2] = 3 + 5 = 8`, which is greater than `nums[1] = 4`. |
| 40 | + - `nums[1] + nums[2] = 4 + 5 = 9`, which is greater than `nums[0] = 3`. |
| 41 | + Since the sum of the two sides is greater than the third side for all three cases, therefore, it can form a triangle. |
| 42 | + As all the sides are of different lengths, it will form a scalene triangle. |
| 43 | + |
| 44 | +### Constraints |
| 45 | + |
| 46 | +- `nums.length == 3` |
| 47 | +- `1 <= nums[i] <= 100` |
| 48 | + |
| 49 | +## Approach |
| 50 | + |
| 51 | +To determine the type of triangle that can be formed by the given sides, we need to: |
| 52 | + |
| 53 | +1. Check if the given sides can form a valid triangle using the triangle inequality theorem. |
| 54 | +2. If the sides form a valid triangle, check if the triangle is equilateral, isosceles, or scalene based on the lengths of the sides. |
| 55 | + |
| 56 | +### Solution Code |
| 57 | + |
| 58 | +#### Python |
| 59 | + |
| 60 | +```python |
| 61 | +class Solution: |
| 62 | + def triangleType(self, nums: List[int]) -> str: |
| 63 | + a, b, c = sorted(nums) |
| 64 | + |
| 65 | + if a + b <= c: |
| 66 | + return "none" |
| 67 | + if a == b == c: |
| 68 | + return "equilateral" |
| 69 | + if a == b or b == c or a == c: |
| 70 | + return "isosceles" |
| 71 | + |
| 72 | + return "scalene" |
| 73 | +``` |
| 74 | + |
| 75 | +#### C++ |
| 76 | +```c++ |
| 77 | +#include <vector> |
| 78 | +#include <string> |
| 79 | +#include <algorithm> |
| 80 | +using namespace std; |
| 81 | + |
| 82 | +class Solution { |
| 83 | +public: |
| 84 | + string triangleType(vector<int>& nums) { |
| 85 | + sort(nums.begin(), nums.end()); |
| 86 | + int a = nums[0], b = nums[1], c = nums[2]; |
| 87 | + |
| 88 | + if (a + b <= c) { |
| 89 | + return "none"; |
| 90 | + } |
| 91 | + if (a == b && b == c) { |
| 92 | + return "equilateral"; |
| 93 | + } |
| 94 | + if (a == b || b == c || a == c) { |
| 95 | + return "isosceles"; |
| 96 | + } |
| 97 | + |
| 98 | + return "scalene"; |
| 99 | + } |
| 100 | +}; |
| 101 | + |
| 102 | +``` |
| 103 | +
|
| 104 | +#### Java |
| 105 | +```java |
| 106 | +import java.util.Arrays; |
| 107 | +
|
| 108 | +class Solution { |
| 109 | + public String triangleType(int[] nums) { |
| 110 | + Arrays.sort(nums); |
| 111 | + int a = nums[0], b = nums[1], c = nums[2]; |
| 112 | + |
| 113 | + if (a + b <= c) { |
| 114 | + return "none"; |
| 115 | + } |
| 116 | + if (a == b && b == c) { |
| 117 | + return "equilateral"; |
| 118 | + } |
| 119 | + if (a == b || b == c || a == c) { |
| 120 | + return "isosceles"; |
| 121 | + } |
| 122 | + |
| 123 | + return "scalene"; |
| 124 | + } |
| 125 | +} |
| 126 | +
|
| 127 | +``` |
| 128 | + |
| 129 | +### Conclusion |
| 130 | +The solutions use a simple sorting approach to determine the type of triangle that can be formed by |
| 131 | +the given sides. This ensures that the problem is solved in a straightforward and efficient manner |
| 132 | +across different programming languages. |
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