JAVA:实现将位置 i 处的字符与位置 j 处的字符交换的函数算法(附完整源码)

package com.thealgorithms.strings;


public class PermuteString {

    //Function for swapping the characters at position I with character at position j    
    public static String swapString(String a, int i, int j) {
        char[] b = a.toCharArray();
        char ch;
        ch = b[i];
        b[i] = b[j];
        b[j] = ch;
        return String.valueOf(b);
    }

    public static void main(String[] args) {
        String str = "ABC";
        int len = str.length();
        System.out.println("All the permutations of the string are: ");
        generatePermutation(str, 0, len);
    }

    //Function for generating different permutations of the string    
    public static void generatePermutation(String str, int start, int end) {
        //Prints the permutations    
        if (start == end - 1) {
            System.out.println(str);
        } else {
            for (int i = start; i < end; i++) {
                //Swapping the string by fixing a character    
                str = swapString(str, start, i);
                //Recursively calling function generatePermutation() for rest of the characters     
                generatePermutation(str, start + 1, end);
                //Backtracking and swapping the characters again.    
                str = swapString(str, start, i);
            }
        }
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40