Daily Coding Problem | Day 1110 | Pythagorean triplet

devstromo · devstromo · commit d0e77eb0fb87 · 2025-04-22T22:22:28.000-03:00
diff --git a/daily-coding-problem/src/main/java/com/devstromo/day1110/Problem.java b/daily-coding-problem/src/main/java/com/devstromo/day1110/Problem.java
@@ -1,5 +1,7 @@
 package com.devstromo.day1110;
 
+import java.util.Arrays;
+
 public class Problem {
     public boolean solve(int[] nums) {
         for (int i = 0; i < nums.length - 2; i++) {
@@ -22,4 +24,40 @@ public boolean solve(int[] nums) {
         }
         return false;
     }
+
+    public boolean solveTwoPointers(int[] nums) {
+        int n = nums.length;
+
+        boolean allZero = Arrays.stream(nums).allMatch(x -> x == 0);
+        if (allZero) return false;
+
+        int[] squared = Arrays.stream(nums)
+                .map(x -> x * x)
+                .toArray();
+
+        Arrays.sort(squared);
+
+        for (int i = n - 1; i >= 2; i--) {
+            if (squared[i] == 0) continue;
+            int left = 0;
+            int right = i - 1;
+
+            while (left < right) {
+                int sum = squared[left] + squared[right];
+
+                if (sum == squared[i]) {
+                    if (squared[left] != 0 || squared[right] != 0) return true;
+                    left++;
+                    right--;
+                } else if (sum < squared[i]) {
+                    left++;
+                } else {
+                    right--;
+                }
+            }
+        }
+
+        return false;
+    }
+
 }
diff --git a/daily-coding-problem/src/test/java/com/devstromo/day1110/ProblemUnitTest.java b/daily-coding-problem/src/test/java/com/devstromo/day1110/ProblemUnitTest.java
@@ -1,5 +1,6 @@
 package com.devstromo.day1110;
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -8,54 +9,37 @@ class ProblemUnitTest {
     private final Problem problem = new Problem();
 
     @Test
-    void testSimpleTriplet() {
-        assertTrue(problem.solve(new int[]{3, 4, 5}));
-    }
-
-    @Test
-    void testMultipleTriplets() {
-        assertTrue(problem.solve(new int[]{10, 4, 6, 8, 5}));
-    }
-
-    @Test
-    void testNoTriplet() {
+    @DisplayName("Test Pythagorean triplet")
+    void testPythagoreanTriplet() {
+        assertFalse(problem.solve(new int[]{0, 0, 0}));
         assertFalse(problem.solve(new int[]{1, 2, 3}));
-    }
-
-    @Test
-    void testEmptyArray() {
-        assertFalse(problem.solve(new int[]{}));
-    }
-
-    @Test
-    void testSingleElement() {
-        assertFalse(problem.solve(new int[]{5}));
-    }
-
-    @Test
-    void testOnlyTwoElements() {
         assertFalse(problem.solve(new int[]{5, 12}));
-    }
-
-    @Test
-    void testWithDuplicates() {
-        assertTrue(problem.solve(new int[]{5, 5, 3, 4}));
-    }
-
-    @Test
-    void testWithZeros() {
-        assertFalse(problem.solve(new int[]{0, 0, 0}));
-    }
-
-    @Test
-    void testNegativeNumbers() {
+        assertFalse(problem.solve(new int[]{5}));
+        assertFalse(problem.solve(new int[]{}));
         assertTrue(problem.solve(new int[]{-3, 4, 5}));
+        assertTrue(problem.solve(new int[]{10, 4, 6, 8, 5}));
         assertTrue(problem.solve(new int[]{3, -4, 5}));
         assertTrue(problem.solve(new int[]{3, 4, -5}));
+        assertTrue(problem.solve(new int[]{3, 4, 5}));
+        assertTrue(problem.solve(new int[]{5, 5, 3, 4}));
+        assertTrue(problem.solve(new int[]{9, 40, 41}));
     }
 
     @Test
-    void testLargeTriplet() {
-        assertTrue(problem.solve(new int[]{9, 40, 41}));
+    @DisplayName("Test Pythagorean triplet with two pointers")
+    void testPythagoreanTripletWithTwoPointers() {
+        assertFalse(problem.solveTwoPointers(new int[]{0, 0, 0}));
+        assertFalse(problem.solveTwoPointers(new int[]{1, 2, 3}));
+        assertFalse(problem.solveTwoPointers(new int[]{5, 12}));
+        assertFalse(problem.solveTwoPointers(new int[]{5}));
+        assertFalse(problem.solveTwoPointers(new int[]{}));
+        assertTrue(problem.solveTwoPointers(new int[]{-3, 4, 5}));
+        assertTrue(problem.solveTwoPointers(new int[]{10, 4, 6, 8, 5}));
+        assertTrue(problem.solveTwoPointers(new int[]{3, -4, 5}));
+        assertTrue(problem.solveTwoPointers(new int[]{3, 4, -5}));
+        assertTrue(problem.solveTwoPointers(new int[]{3, 4, 5}));
+        assertTrue(problem.solveTwoPointers(new int[]{5, 5, 3, 4}));
+        assertTrue(problem.solveTwoPointers(new int[]{9, 40, 41}));
     }
+
 }
