Delegate Quick Scanner

QScanner.java

//import java.io.*; import java.util.*;

/**
 * Delegate quick Scanner. Example usage: <pre>QScanner scanner = new QScanner(System.in);</pre>
 */
@SuppressWarnings({"unused", "Duplicates"}) //noinspection Duplicates
public class QScanner {
    java.io.BufferedReader br; java.util.StringTokenizer st;

    public QScanner() { br = new java.io.BufferedReader(new java.io.InputStreamReader(System.in)); }

    public QScanner(java.io.InputStream is) {
        br = new java.io.BufferedReader(new java.io.InputStreamReader(new java.io.DataInputStream(is)));
    }

    public String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new java.util.StringTokenizer(br.readLine());
            } catch (java.io.IOException e) { e.printStackTrace(); }
        }
        return st.nextToken();
    }

    public int nextInt() { return Integer.valueOf(next()); }

    public long nextLong() { return Long.valueOf(next()); }

    public double nextDouble() { return Double.valueOf(next()); }

    public void close() {
        if (br != null) { try { br.close(); } catch (java.io.IOException e) { e.printStackTrace(); } }
    }
}

Java template "input scanner" for coding challenges that need quick input.
It is useful for competitive programming (SPOJ, CodeForges, VNOJ, Timus, AtCoder, UVA, USACO, Kattis, TopCoder, CodeChef, HackerEarth, Kaggle, ...),
and also useful for interview grinders (HackerRank/LeetCode/GFG/Codingame/Codility/TestDome/CodeSignal/Codecademy/Codewars/EDABit/BitDegree/...)

The quick scanner can be customized a bit to adapt to your need. Examples:

https://github.com/ducquoc/euler-fun/blob/master/euler/src/main/java/vn/ducquoc/euler/HR034.java#L50
https://raw.githubusercontent.com/dqonline/pic/main/u/TECH/VNOJ_LIS_sample.png
...