How do i find the duplicates in java array-CodePudding

I am trying to make it so if there are any duplicates in the array, it turns true and if there is not it turns false. But, no matter what I do the if statement always turns in into false, even if there isn't a duplicate. This has to be done as a boolean.

 int array[] = {10, 20, 30, 10, 40, 50};

 public boolean hasDuplicates2() {
   for (int i = 0; i <= array.length; i  ) {
     for (int i2 = 1; i2 <= array.length - 1; i2  ) {
       if (array[i] != array[i2]) {
         return false;
       }
     }
   }
   return true;
 }

CodePudding user response：

public static void main(String[] args) {

    int array[] = {10, 20, 30, 10, 40, 50};
    System.out.println(hasDuplicates(array));
}

public static boolean hasDuplicates(int[] array) {
    var distinct = Arrays.stream(array).distinct().count();
    return distinct != array.length;
}

CodePudding user response：

your code return false because its stops when first cycle says its false and after that your for statement return false instead of "return false" you can change a bit

public boolean hasDuplicates2() 
{
  bool hasDuclicates = false;
  for (int i = 0; i <= array.length; i  ) {
   for (int i2 = 1; i2 <= array.length - 1; i2  ) {
    if (array[i] == array[i2]) {
     hasDuplicates = true;
    }
   }
  }
  return hasDuplicates;
}

it may not be efficient by the way

CodePudding user response：

So a couple of problems:

1)You need to have array.length - 1 even in the first for loop, or you're going to go out of range at the last iteration.

2)You're checking each and every element including the element itself - which means when i = i2, you're always going to satisfy the if condition, so you need to check for that as well.

Try this:

public static boolean hasDuplicates2(int[] array) {
    for (int i = 0; i <= array.length - 1; i  ) {
        for (int i2 = 1; i2 <= array.length - 1; i2  ) {
            if (i != i2 && array[i] == array[i2]) {
                return true;
            }
        }
    }
    return false;
}