check if three arrays have the same value

Question

I put numbers of three people in one arraylist and in the case if three people have the same number then overall occurrences++; this is my algorithm but it is not working for this case!!

5 (first person has 5 nums)
13 20 22 43 146

4 (second person has 4 nums)
13 22 43 146

5 (third person has 5 nums)
13 43 67 89 146

int occurrences = 0;
for (int i = 0; i<n; ++i){
    for (int j = n; j<n+b; ++j ){
        if(arr.get(i)==arr.get(j)){
            System.out.println(arr.get(i)+" " +arr.get(j));
            for(int k=n+b; k<arr.size(); ++k){
                if(arr.get(j)==arr.get(k)){
                    ++occurrences;
                    System.out.println(arr.get(k));
                }
            }
        }
    }
}

What's the type of data in the ArrayList? Strings? Integers? Longs? — Eran, Oct 30 '14 at 11:48
Too bad. If they were Strings, I know which question that would be duplicate of. Anyway, don't compare them with ==. Use equals. — Eran, Oct 30 '14 at 11:50
I wish you'd share with us such mysteries such as what `b` is exactly. Or what is it you want, exactly. — RealSkeptic, Oct 30 '14 at 11:54
i want to know how many numbers are repeated for three of them!!!n=5; b =4 — halu, Oct 30 '14 at 12:00
still confused with what u really want ....there is a list of integers and you want how many number are repeated in a list is that what u want????? — amit bhardwaj, Oct 30 '14 at 12:10
Can a person have numbers repeated? Ex. first person has 2 13's? — coder hacker, Oct 30 '14 at 12:12
If you want to compare two lists for common values see below URL. http://stackoverflow.com/questions/5943330/common-elements-in-two-lists — , Oct 30 '14 at 12:17

amit bhardwaj · Answer 1 · 2014-10-30T13:05:02.630

try this if you have 3 array of 3 person

public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter numbers for 1st person seprated by ',' like 1,2,3....");
    String noForFirst = sc.nextLine();
    String[] a = noForFirst.split(",");
    System.out.println("Enter numbers for 2nd person seprated by ',' like 1,2,3....");
    String noForSecond = sc.nextLine();
    String[] b = noForSecond.split(",");
    System.out.println("Enter numbers for 3rd person seprated by ',' like 1,2,3....");
    String noForThird = sc.nextLine();
    String[] c = noForThird.split(",");
    int occurrences = 0;
    for (int i = 0; i < a.length; ++i) {
        for (int j = 0; j < b.length; ++j) {
            if (a[i].equals(b[j])) {
                for (int k = 0; k < c.length; ++k) {
                    if (a[i].equals(c[k])) {
                        ++occurrences;
                        System.out.println(a[i]);
                    }
                }
            }
        }
    }
    System.out.println("occurrences = " + occurrences);

Input

Enter numbers for 1st person seprated by ',' like 1,2,3.... 1,5,9,7,6 Enter numbers for 2nd person seprated by ',' like 1,2,3.... 1,4,8,7,3,5 Enter numbers for 3rd person seprated by ',' like 1,2,3.... 1,7,2

output

1 7 occurrences = 2

yes this is ok, but what i need to get input from user and i don't know how many element each array will contain!!!! — halu, Oct 30 '14 at 12:41
dosen't matter after taking input just put the values in differnt array and same code is good to go — amit bhardwaj, Oct 30 '14 at 12:48

check if three arrays have the same value

1 Answers1