如何在Java中实现输入"add 5"累加、"set 5"初始化变量？

Got it, let's break this down step by step. You need to handle two specific commands: set X (which initializes your stored value to X) and add X (which adds X to the current stored value). Since the function is named maximumProgramValue, we'll also make sure we never let the value drop below 0—because adding a negative number could pull it into negatives, and we want to keep the highest possible value at all times.

Here's the complete, working code that fills in your provided framework:

import java.io.*;
import java.math.*;
import java.text.*;
import java.util.*;
import java.util.regex.*;

public class Solution {

    /*
     * Complete the maximumProgramValue function below.
     */
    static long maximumProgramValue(int n) {
        // Start with a default value of 0
        long currentValue = 0;
        
        for (int i = 0; i < n; i++) {
            // Grab the command type and the associated number
            String command = scanner.next();
            long number = scanner.nextLong();
            
            if ("set".equals(command)) {
                // Overwrite the current value with the given number
                currentValue = number;
            } else if ("add".equals(command)) {
                // Add the number, but don't let the value go negative
                currentValue += number;
                // If adding makes it negative, reset to 0 to preserve the maximum possible value
                if (currentValue < 0) {
                    currentValue = 0;
                }
            }
        }
        
        return currentValue;
    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        long result = maximumProgramValue(n);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedWriter.close();
        scanner.close();
    }
}

Key Details Explained: #

• Long Data Type: We use long instead of int to avoid integer overflow—critical if you're dealing with large numbers or a high volume of add commands.
• Simple Command Parsing: Using scanner.next() and scanner.nextLong() is cleaner than splitting strings, since the input format is always a command followed by a number.
• Non-Negative Guard: The "maximum" in the function name implies we shouldn't hold onto negative values. If an add would make the value negative, we reset it to 0—there's no upside to keeping a negative value when we can start fresh from zero.
• Main Function Setup: The main method handles input/output as typical in coding challenges—reading the number of commands, executing the logic, and writing the result to the specified output file.

Example Test Case: #

If you run with n=4 and these commands:

1. set 5 → currentValue = 5
2. add 3 → currentValue = 8
3. add -10 → would become -2, so we reset to 0
4. add 7 → currentValue = 7

The final result returned would be 7.

内容的提问来源于stack exchange，提问作者Rupendra Singh