Integer partition in java store output in an array

Question

I have the following code from Print all unique integer partitions given an integer as input

void printPartitions(int target, int maxValue, String suffix) {
    if (target == 0)
        System.out.println(suffix);
    else {
        if (maxValue > 1)
            printPartitions(target, maxValue-1, suffix);
        if (maxValue <= target)
            printPartitions(target-maxValue, maxValue, maxValue + " " + suffix);
    }
}

When it calls printPartitions(4, 4, ""); it gives the below output:

How can I get the output in an array like this:

[[1,1,1,1],[1,1,2],[2,2],[1,3],[4]]

score 0 · Answer 1 · answered May 28 '17 at 15:57

You should collect your values to an array in this case. I've replaced the array with a list, for simplification of "add" operation (for an array you should maintain also indexes):

void printPartitions(int target, int maxValue, List<String> suffix, List<List<String>> list) {
    if (target == 0) {
        list.add(suffix);
    } else {
        if (maxValue > 1)
            printPartitions(target, maxValue-1, suffix, list);
        if (maxValue <= target) {
            List<String> tmp = new ArrayList<String>();
            tmp.add(0, String.valueOf(maxValue));
            tmp.addAll(suffix);
            printPartitions(target-maxValue, maxValue, tmp, list);
        }
    }
}

void callPrintPartitions() {
    List<List<String>> list = new ArrayList<List<String>>();
    printPartitions(4, 4, new ArrayList<String>(), list);
    System.out.println(list);
}

Output:

[[1, 1, 1, 1], [1, 1, 2], [2, 2], [1, 3], [4]]

Integer partition in java store output in an array

1 Answers1