我的代码没有给我正确的输出。它从文本文件中读取数字，将其转换为整数值并对其进行一些乘法。但是方法findProduct()给我的产品是错误的，所以我认为我使用了错误的Integer.parseInt()方法。
我想让我失望的是，它试图告诉我96086x67017 = 2144428166的乘积，在检查我的计算器时，它大约是643939395462。
/*
*
* Find the greatest product of five consecutive digits in the 1000-digit number.
73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450
this text file is in Project_8.txt
*/
import java.io.*;
// Import the scanner class that is used for reading the text file
import java.util.*;
public class Project_8 {
// Data members================================
// Object used to read the text file
private Scanner scanner;
// Public Methods==============================
// Points the scaaner object in the direction of the text file. Outputs an error if file is not found
public void openFile(){
try{
// Note the whole file's path is required
scanner = new Scanner(new File("/Users/nicolematthews/Desktop/Tim/Java WORKSPACE/Project_Euler/src/Project_8.txt"));
}catch(Exception e){
System.out.println("Could not find the File. Check file's address");
}
}
public String readFile(){
// Instantiating the scanner for user input ruins its application for reading files
//scanner = new Scanner(System.in);
// Method looks the text file and adds each line of the text to the String sequence.
// the Method returns sequence
String sequence = "";
// While the scanner has more data to read
while(scanner.hasNext()){
sequence = sequence + scanner.next();
}
return sequence;
}
// This method simply closes the scanner object
public void closeFile(){
scanner.close();
}
public int findProduct(String sequence){
int highestProduct = 0;
for(int i = 0; i < ( sequence.length() - 10 ); i++){
// Extract adjacent 5 digit strings which will be converted to integers
String num1 = sequence.substring(i, i + 5);
String num2 = sequence.substring(i + 5, i + 10);
if( Integer.parseInt(num1)*Integer.parseInt(num2) > highestProduct ){
highestProduct = Integer.parseInt(num1)*Integer.parseInt(num2);
System.out.println(num1);
System.out.println(num2);
System.out.println(highestProduct);
System.out.println("\n");
}
}
return highestProduct;
}
// Main Method =========================================
public static void main(String args[] ) throws IOException{
Project_8 object = new Project_8();
object.openFile();
String Sequence = object.readFile();
System.out.println(Sequence);
System.out.printf("%d Is the highest product of five consecutive \n" +
"digits in the 1000-digit number.", object.findProduct(Sequence));
// Finally, close the file when we are done with it.
object.closeFile();
/* Find the greatest product of five consecutive digits in the 1000-digit number
System.out.println(Sequence);
*/
}
}
最佳答案
您的序列索引i对于每次迭代i++仅前进1，但是每次迭代消耗10个字符。您已经表明这是您的意图。
您将在Java int中溢出数据中的许多5位子序列。例如，您的第二个产品将是31671 * 76531 = 2423813301。比Integer.MAX_INT大：2 ^ 31-1。
将findProduct方法更改为使用long和Long.parseLong()将解决此问题。
关于java - Integer.parseInt()问题，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/11593917/