Question

How to find the shortest identical consecutive subvector in an vector with Java

Answer 1

import java.util.Vector; 
import java.util.Arrays; 
 
public class ShortestRunProgram {
 
    public static Vector<Integer> shortest_identical_consecutive_subvector(Vector<Integer> vec) {
        if (vec.isEmpty()) return new Vector<>();
 
        int bestStart = 0;
        int bestLen = vec.size();
 
        int currentStart = 0;
        int currentLen = 1;
 
        for (int i = 1; i < vec.size(); i++) {
            if (vec.get(i).equals(vec.get(i - 1))) {
                currentLen++;
            } else {
                if (currentLen < bestLen) {
                    bestLen = currentLen;
                    bestStart = currentStart;
                }
                currentStart = i;
                currentLen = 1;
            }
        }
 
        if (currentLen < bestLen) {
            bestLen = currentLen;
            bestStart = currentStart;
        }
 
        Vector<Integer> result = new Vector<>();
        for (int i = bestStart; i < bestStart + bestLen; i++) {
            result.add(vec.get(i));
        }
 
        return result;
    }
 
    // ------------------------------------------------------------
    // MAIN PROGRAM
    // ------------------------------------------------------------
    public static void main(String[] args) {
 
        Vector<Integer> vec = new Vector<>(Arrays.asList(3,3,3, 7,7,7,7,7, 2,2, 5,5,5,5, 9,9,9,9,9,9));

        Vector<Integer> resultVec = shortest_identical_consecutive_subvector(vec);
        System.out.print("Vector result: ");
        for (int x : resultVec) System.out.print(x + " ");
    }
}
 
 
/*
run:
 
Vector result: 2 2 
 
*/

 

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