如何在代码中为每个循环代替for循环添加? [英] How can I add for each loop in place of for loop in my code?
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问题描述
我如何为代码中的for循环添加每个循环?有没有办法提高我的代码性能?提前致谢
How can i add for each loop in place of for loop in my code? Is there any possible way to increase performance in my code? Thanks in advance
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;
public class permutation {
static Scanner s=new Scanner(System.in);
static String
input =s.nextLine();
static int size = s.nextInt();
static boolean[] num = new boolean[input.length()];
static FileWriter fstream =null;
public static void generate(String data, BufferedWriter out) {
if (data.length() == size) {
try {
out.newLine();
out.write(data);
} catch (IOException e) {
e.printStackTrace();
}
return;
}
for (int i = 0; i < input.length(); ++i) {
if (!num[i]) {
num[i] = true;
generate(data + input.charAt(i), out);
num[i] = false;
}
}
}
public static void main(String[] args) throws Exception {
fstream = new FileWriter("D:\\out2.txt",true);
BufferedWriter out=new BufferedWriter(fstream);
char[] chars = input.toCharArray();
Arrays.sort(chars);
String sorted = new String(chars);
input=sorted;
generate("", out);
out.close();
}
}
我的尝试:
我无法从对象转换为整数
What I have tried:
Iam unable to typecast from object to integer
推荐答案
用foreach代替for,虽然可能,但是不切实际(而且很难看)。在任何情况下,你都不会获得任何性能上的提升。
Substituting the for with foreach, though possible, would be impractical (and ugly). In any case you wouldn't get any performance gain, with such replacement.
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