Q: Collect Resources - Java Task

+10 votes

Stamat got totally hooked on the newest strategy game and literally can’t stop playing it. The game involves building an army and crushing your opponents, but to build an army, you need resources. The game has a rather unusual resource collection system – you are given the available resources and several possible ways to collect them. It’s up to you to decide what the optimal path is.

The resources are handed to you as an array of elements in format [resource_quantity resource_quantityresource_quantity]. Valid resources are stone, gold, wood and food. When you step on a resource, you collect it. All of them have the same value, so wood_3 is equal to gold_3. NOTE: when there is only one piece of a given resource, it can be written as wood or wood_1 (both are valid).

You are also given several different ways to collect the resources – start and step. The start is the zero-based position you start from, and step is the number of elements you move to the right. If you reach the end of the resource field, you go back to its start. If the element you jump on is a valid resource, you collect it. The process ends when you reach an element you have already collected.

For example, you have resource field stone_5 gold_3 water_2 wood_7 and start: 0; step: 2. You start from stone_5 and collect 5 resources. You move two elements to the right and step on water_2, which is not a valid resource, so you collect nothing. You move another two elements to the right, but this is outside of the element field, so you have to start from the beginning, which is stone_5 again. It is already collected, so you stop with the process. You have gathered 5 resources total. NOTE: invalid resources are never collected.

Write a program that examines several possible ways to collect resources from the same field and outputs the maximum possible collectable quantity.


  • On the first line of input, you are given the resource field.
  • On the second line, you are given the integer N – the number of collection paths
  • On the next N lines you are given the start and step for the given path – both integers, separated by a space.


  • There is one line of output – the maximum possible quantity that can be collected from any of the patterns


  • The quantity is in range [1 … 100]
  • The number of lines N is in range [1 … 10]
  • The start index is always inside the resource field. The step is a valid positive integer.
  • Allowed time/memory 0.1s (C#) 0.25s (Java)/16MB


example collect resources - java task

asked in Java category by user eiorgert
edited by user golearnweb

1 Answer

+2 votes
Best answer

Here's my solution my friend:


import java.util.Scanner;

public class CollectResources {
    public static void main(String[] args) {
        Scanner console = new Scanner(;
        String[] items = console.nextLine().split("\\s+");
        boolean[] itemsFlags = new boolean[items.length];

        int tests = console.nextInt();

        long maxQuantity = 0;
        int currentQuantity = 0;
        int currentPosition;

        for (int test = 0; test < tests; test++) {
            currentQuantity = 0;
            itemsFlags = new boolean[items.length];
            String[] input = console.nextLine().trim().split("\\s+");
            int start = Integer.parseInt(input[0]);
            int step = Integer.parseInt(input[1]);
            currentPosition = start;
            step %= items.length;

            while (!itemsFlags[currentPosition]) {
                String[] resourceData = items[currentPosition].split("_");
                String resourceType = resourceData[0];
                int quantity;
                if (resourceData.length == 1) {
                    quantity = 1;
                } else {
                    quantity = Integer.parseInt(resourceData[1]);
                switch (resourceType) {
                    case "stone":
                    case "gold":
                    case "wood":
                    case "food":
                        currentQuantity += quantity;
                        itemsFlags[currentPosition] = true;
                currentPosition += step;
                currentPosition %= items.length;
            if (currentQuantity > maxQuantity) {
                maxQuantity = currentQuantity;


answered by user hues
selected by user golearnweb