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Copy pathArrayOperations.java
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76 lines (65 loc) · 1.99 KB
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import java.util.*;
public class ArrayOperations {
// Find maximum element in array
public int findMax(int[] arr) {
int max = arr[0];
for (int i = 1; i < arr.length; i++) {
if (arr[i] > max) max = arr[i];
}
return max;
}
// Reverse array in-place
public void reverseArray(int[] arr) {
int left = 0, right = arr.length - 1;
while (left < right) {
int temp = arr[left];
arr[left] = arr[right];
arr[right] = temp;
left++;
right--;
}
}
// Find missing number in array 1 to n
public int findMissing(int[] arr, int n) {
int sum = n * (n + 1) / 2;
for (int num : arr) {
sum -= num;
}
return sum;
}
// Remove duplicates from sorted array
public int removeDuplicates(int[] arr) {
if (arr.length == 0) return 0;
int j = 0;
for (int i = 1; i < arr.length; i++) {
if (arr[i] != arr[j]) {
arr[++j] = arr[i];
}
}
return j + 1;
}
// Rotate array right by k positions
public void rotateRight(int[] arr, int k) {
k %= arr.length;
reverse(arr, 0, arr.length - 1);
reverse(arr, 0, k - 1);
reverse(arr, k, arr.length - 1);
}
private void reverse(int[] arr, int start, int end) {
while (start < end) {
int temp = arr[start];
arr[start] = arr[end];
arr[end] = temp;
start++;
end--;
}
}
public static void main(String[] args) {
ArrayOperations ap = new ArrayOperations();
int[] arr = {3, 1, 4, 1, 5, 9, 2, 6};
System.out.println("Max: " + ap.findMax(arr));
ap.reverseArray(arr);
System.out.println("Reversed: " + Arrays.toString(arr));
System.out.println("Missing: " + ap.findMissing(new int[]{1,2,4,5}, 5));
}
}