дз 18 roman to integer

pom.xml

@@ -13,5 +13,5 @@
         <maven.compiler.target>18</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
-    
+
 </project>

src/main/java/Main.java

@@ -0,0 +1,92 @@
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) {
+      //palindrome
+        Scanner scanner = new Scanner(System.in);
+        System.out.print("Введіть текст: ");
+        String input = scanner.nextLine();
+        String cleanText = input.replaceAll("[^a-zA-Zа-яА-Я0-9]", "");
+        String lowercaseText = cleanText.toLowerCase();
+
+        if (isPalindrome(lowercaseText)) {
+            System.out.println("Текст є паліндромом.");
+        } else {
+            System.out.println("Текст не є паліндромом.");
+        }
+
+        //arrays
+        int[] nums1 = {1,2,3,1}; //true
+        int[] nums2 = {1,2,3,4}; //false
+        int[] nums3 = {1,1,1,3,3,4,3,2,4,2}; //true
+        System.out.println(containsDuplicate(nums1));
+        System.out.println(containsDuplicate(nums2));
+        System.out.println(containsDuplicate(nums3));
+
+        //arrays+target
+        int[] nums_1 = {2,7,11,15};
+        int target_1 = 9;
+        int[] nums_2 = {3,2,4};
+        int target_2 = 6;
+        int[] nums_3 = {3,3};
+        int target_3 = 6;
+
+        System.out.println(Arrays.toString(twoSum(nums_1,target_1)));
+        System.out.println(Arrays.toString(twoSum(nums_2,target_2)));
+        System.out.println(Arrays.toString(twoSum(nums_3,target_3)));
+
+        //maxProfit
+        int[] prices1 = {7,1,5,3,6,4};//5
+        int[] prices2 = {7,6,4,3,1};//0
+        System.out.println(MaxProfit.maxProfit(prices1));
+        System.out.println(MaxProfit.maxProfit(prices2));
+
+        //reverseArray
+        int[] startArray = {1,2,3,4,5};
+        System.out.println("Start array: "+Arrays.toString(startArray));
+        System.out.println("Reversed array: "+Arrays.toString(ReverseArray.reverseArray(startArray)));
+
+        //romanToInt
+        System.out.println(RomanToInteger.romanToInt("III"));
+        System.out.println(RomanToInteger.romanToInt("LVIII"));
+        System.out.println(RomanToInteger.romanToInt("MCMXCIV"));
+
+
+    }
+    private static boolean isPalindrome(String text) {
+        int length = text.length();
+        for (int i = 0; i < length / 2; i++) {
+            if (text.charAt(i) != text.charAt(length - 1 - i)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private static boolean containsDuplicate(int[] nums) {
+        Set<Integer> set = new HashSet<>();
+        for (int num : nums) {
+            if (set.contains(num)) {
+                return true;
+            }
+            set.add(num);
+        }
+        return false;
+    }
+
+    private static int[] twoSum(int[] nums, int target) {
+        int[] result = new int[2];
+        Map<Integer, Integer> map = new HashMap<>();
+
+        for (int i = 0; i < nums.length; i++) {
+            int complement = target - nums[i];
+            if (map.containsKey(complement)) {
+                result[0] = map.get(complement);
+                result[1] = i;
+                break;
+            }
+            map.put(nums[i], i);
+        }
+        return result;
+    }
+}

src/main/java/MaxProfit.java

@@ -0,0 +1,16 @@
+public class MaxProfit {
+    public static int maxProfit(int[] prices) {
+        int maxProfit = 0;
+        int minPrice = Integer.MAX_VALUE;
+
+        for (int i = 0; i < prices.length; i++) {
+            if (prices[i] < minPrice) {
+                minPrice = prices[i];
+            } else if (prices[i] - minPrice > maxProfit) {
+                maxProfit = prices[i] - minPrice;
+            }
+        }
+
+        return maxProfit;
+    }
+}

src/main/java/ReverseArray.java

@@ -0,0 +1,16 @@
+public class ReverseArray {
+    public static int[] reverseArray(int[] array) {
+        int start = 0;
+        int end = array.length - 1;
+
+        while (start < end) {
+            int temp = array[start];
+            array[start] = array[end];
+            array[end] = temp;
+            start++;
+            end--;
+        }
+
+        return array;
+    }
+}

src/main/java/RomanToInteger.java

@@ -0,0 +1,32 @@
+import java.util.HashMap;
+
+public class RomanToInteger {
+    public static int romanToInt(String s) {
+        HashMap<Character, Integer> symbolValues = new HashMap<>();
+        symbolValues.put('I', 1);
+        symbolValues.put('V', 5);
+        symbolValues.put('X', 10);
+        symbolValues.put('L', 50);
+        symbolValues.put('C', 100);
+        symbolValues.put('D', 500);
+        symbolValues.put('M', 1000);
+
+        int result = 0;
+        int prevValue = 0;
+
+        for (int i = s.length() - 1; i >= 0; i--) {
+            char currentSymbol = s.charAt(i);
+            int currentValue = symbolValues.get(currentSymbol);
+
+            if (currentValue >= prevValue) {
+                result += currentValue;
+            } else {
+                result -= currentValue;
+            }
+
+            prevValue = currentValue;
+        }
+
+        return result;
+    }
+}