Create 3024-type-of-triangle.java

Author: sanajitjana

Easy/3024-type-of-triangle.java

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+/**
+ * Question: Determine Triangle Type
+ * Link: https://leetcode.com/problems/triangle-type/ (hypothetical link, adjust if needed)
+ *
+ * Description:
+ * Given three side lengths of a triangle, return the type of the triangle:
+ *   - "equilateral" if all sides are equal
+ *   - "isosceles" if exactly two sides are equal
+ *   - "scalene" if all sides are different
+ *   - "none" if the given sides cannot form a valid triangle
+ *
+ * Approach:
+ * 1. Extract the three sides.
+ * 2. Check the triangle inequality: sum of any two sides must be greater than the third.
+ *    If it fails, return "none".
+ * 3. If all three sides are equal, return "equilateral".
+ * 4. If exactly two sides are equal, return "isosceles".
+ * 5. Otherwise, return "scalene".
+ *
+ * Dry Run:
+ * Example: nums = [3, 4, 5]
+ *  - Check: 3+4 > 5, 3+5 > 4, 4+5 > 3 → valid triangle
+ *  - Not all sides equal
+ *  - No two sides equal
+ *  - Result → "scalene"
+ *
+ * Example: nums = [2, 2, 2]
+ *  - Check: valid triangle
+ *  - All equal → "equilateral"
+ *
+ * Example: nums = [2, 3, 5]
+ *  - Check: 2+3 = 5 → fails inequality
+ *  - Result → "none"
+ *
+ * Time Complexity: O(1) → only a few comparisons.
+ * Space Complexity: O(1) → no extra data structures used.
+ */
+
+class Solution {
+    public String triangleType(int[] nums) {
+        
+        int s1 = nums[0];
+        int s2 = nums[1];
+        int s3 = nums[2];
+
+        // Check triangle inequality
+        if (s1 + s2 <= s3 || s1 + s3 <= s2 || s2 + s3 <= s1) {
+            return "none";
+        }
+
+        // All sides equal
+        if (s1 == s2 && s2 == s3) {
+            return "equilateral";
+        } 
+        // Any two equal
+        else if (s1 == s2 || s2 == s3 || s1 == s3) {
+            return "isosceles";
+        } 
+        // Otherwise scalene
+        else {
+            return "scalene";
+        }
+    }
+}