Question

Program in java

1- Implement an algorithms to calculate the sum of all numbers in an array.  

2- Implement an algorithm to determine if an array has all unique integer values.

3- Given an array nums. We define a running sum of an array as runningSum[i] = sum(nums[0]…nums[i]).

Return the running sum of nums.

Example 1:

Input: nums = [1,2,3,4]
Output: [1,3,6,10]
Explanation: Running sum is obtained as follows: [1, 1+2, 1+2+3, 1+2+3+4].

Answer 1

/*If you have any query do comment in the comment section else like the solution*/

import java.util.*;
public class ArrayUtil{
     public static void main(String []args){
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter size of array : ");
        int n = sc.nextInt();
        int arr[] = new int[n];
        for(int i=0;i<n;i++) {
            arr[i] = sc.nextInt();
        }
        runningSum(arr, n);
        if(isUnique(arr, n)) {
            System.out.println("Array is unique");
        } else {
            System.out.println("Array is not unique");
        }
     }
     
     public static void runningSum(int arr[], int n) {
        int i, sum = 0;
        int prefixSum[] = new int[n];
        prefixSum[0] = arr[0];
        for(i=1;i<n;i++) {
            prefixSum[i] = arr[i] + prefixSum[i-1];
        }
        for(i=0;i<n;i++) {
            System.out.print(prefixSum[i] + " ");
        }
        System.out.println();
     }
     
     public static boolean isUnique(int arr[], int n) {
        int i, j;
        for(i=0;i<n;i++) {
            for(j=i+1;j<n;j++) {
                if(arr[i] == arr[j]) {
                    return false;
                }
            }
        }
        return true;
     }
}

Input:

1 2 3 4

Output:

1 3 6 10 
Array is unique