Hackerrank30天编程挑战Day6 Java：输出格式问题致测试不通过

Looks like your code failed the test cases because you're printing the even-indexed and odd-indexed character strings on separate lines instead of the same line separated by a space. Let's fix that!

What Went Wrong #

Most likely, you used two separate System.out.println() calls to print the even and odd strings. Each println() adds a newline character at the end, which splits your output into two lines—violating the problem's requirement of a single line per test case.

Solution Code #

Here's a corrected version of your Java code that meets all the problem requirements:

import java.util.Scanner;

public class StringSplit {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int testCases = scanner.nextInt();
        scanner.nextLine(); // Consume the leftover newline after reading integer T
        
        for (int i = 0; i < testCases; i++) {
            String input = scanner.nextLine();
            StringBuilder evenStr = new StringBuilder();
            StringBuilder oddStr = new StringBuilder();
            
            for (int idx = 0; idx < input.length(); idx++) {
                char c = input.charAt(idx);
                if (idx % 2 == 0) {
                    evenStr.append(c);
                } else {
                    oddStr.append(c);
                }
            }
            
            // Print both strings in one line, separated by a space
            System.out.println(evenStr + " " + oddStr);
        }
        scanner.close();
    }
}

Key Details to Note #

• StringBuilder for Efficiency: Since the input string can be up to 10000 characters long, using StringBuilder is far more efficient than concatenating strings with + (which creates unnecessary intermediate string objects).
• Handling Input Correctly: After reading the number of test cases with nextInt(), we call scanner.nextLine() to consume the newline character left in the input buffer. If we skip this, the first nextLine() call will read an empty string instead of the first test case's string.
• Single-Line Output: The critical fix is using a single System.out.println() to print both the even and odd strings, separated by a space. This ensures they appear on the same line as required.

Edge Case Handling #

If the input string has an odd length, the odd-indexed string will be one character shorter than the even-indexed one. This is completely acceptable per the problem constraints—no extra code is needed to handle this.

内容的提问来源于stack exchange，提问作者Ankita