Add chinese remainder theorem (#5873)

src/test/java/com/thealgorithms/maths/ChineseRemainderTheoremTest.java

@@ -0,0 +1,54 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+public class ChineseRemainderTheoremTest {
+    @Test
+    public void testCRTSimpleCase() {
+        List<Integer> remainders = Arrays.asList(2, 3, 2);
+        List<Integer> moduli = Arrays.asList(3, 5, 7);
+        int expected = 23;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTLargeModuli() {
+        List<Integer> remainders = Arrays.asList(1, 2, 3);
+        List<Integer> moduli = Arrays.asList(5, 7, 9);
+        int expected = 156;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTWithSingleCongruence() {
+        List<Integer> remainders = Arrays.asList(4);
+        List<Integer> moduli = Arrays.asList(7);
+        int expected = 4;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTWithMultipleSolutions() {
+        List<Integer> remainders = Arrays.asList(0, 3);
+        List<Integer> moduli = Arrays.asList(4, 5);
+        int expected = 8;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void testCRTLargeNumbers() {
+        List<Integer> remainders = Arrays.asList(0, 4, 6);
+        List<Integer> moduli = Arrays.asList(11, 13, 17);
+        int expected = 550;
+        int result = ChineseRemainderTheorem.solveCRT(remainders, moduli);
+        assertEquals(expected, result);
+    }
+}