Java/src/main/java/com/string/Interleave.java at Development · ailvcheng/Java · GitHub

History

151 lines (134 loc) · 5.79 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

package com.string;

import org.junit.Test;

import java.util.ArrayList;

import java.util.List;

import static org.junit.Assert.assertEquals;

public class Interleave {

@Test

public void testInterleaveRegularString() {

String string1 = "Hello";

String string2 = "World";

String expected = "HWeolrllod";

String actual = interleave(string1, string2);

assertEquals("Incorrect result from method.", expected, actual);

}

@Test

public void testInterleaveEmptyString() {

String string1 = "";

String string2 = "";

String string3 = "a";

String string4 = "abc";

String expected1 = "";

String actual1 = interleave(string1, string2);

String expected2 = "a";

String actual2 = interleave(string1, string3);

String expected3 = "abc";

String actual3 = interleave(string1, string4);

assertEquals("Incorrect result from method.", expected1, actual1);

assertEquals("Incorrect result from method.", expected2, actual2);

assertEquals("Incorrect result from method.", expected3, actual3);

}

@Test

public void testInterleaveSingleString() {

String string1 = "a";

String string2 = "b";

String expected = "ab";

String actual = interleave(string1, string2);

assertEquals("Incorrect result from method.", expected, actual);

}

@Test

public void testInterleaveIntString() {

String string1 = "1";

String string2 = "7";

String expected = "17";

String actual = interleave(string1, string2);

assertEquals("Incorrect result from method.", expected, actual);

}

@Test

public void testInterleaveMixedString() {

String string1 = "1a2b3c4d";

String string2 = "5e6f7g8h";

String expected = "15ae26bf37cg48dh";

String actual = interleave(string1, string2);

assertEquals("Incorrect result from method.", expected, actual);

}

@Test

public void testInterleaveSymbols() {

String string1 = "a@b%c/";

String string2 = "d#e$g%.";

String expected = "ad@#be%$cg/%.";

String actual = interleave(string1, string2);

assertEquals("Incorrect result from method.", expected, actual);

}

@Test

public void testInterleaveSpaces() { // This string interleave algorithm defines a space as a valid character.

String string1 = " ";

String string2 = "a";

String string3 = "5 g";

String string4 = " 4 d ";

String expected1 = " a";

String actual1 = interleave(string1, string2);

String expected2 = "a5 g";

String actual2 = interleave(string2, string3);

String expected3 = "5 4g d ";

String actual3 = interleave(string3, string4);

assertEquals("Incorrect result from method.", expected1, actual1);

assertEquals("Incorrect result from method.", expected2, actual2);

assertEquals("Incorrect result from method.", expected3, actual3);

}

/**

* This method "interweaves" two input strings one character at a time. The first character of the

* first parameter string always starts the resulting string, unless that character is a space or is empty.

* This string interleaving method takes a space in a string (e.g. " ") into consideration.

* For example, if string1 = "abc" and string2 = "def", then the result would be "adbecf", as the first character

* of the string1 is 'a', then the first character of string2 is 'd', and so forth.

* For more information on interleaving, check out: https://en.wikipedia.org/wiki/Interleave_sequence

* @param string1

* @param string2

* @return string resulting from the interweaving of the two input strings; string1 and string2.

public String interleave(String string1, String string2) {

String result = ""; // The final interleaved string to return.

List<Character> list1 = new ArrayList<>(); // The ArrayList of string1, with each character being an individual element.

List<Character> list2 = new ArrayList<>(); // The ArrayList of string2, in a similar manner as above.

for (int i = 0; i < string1.length(); i++) // Convert string1 into list1.

list1.add(string1.charAt(i));

for (int i = 0; i < string2.length(); i++) // Convert string2 into list2.

list2.add(string2.charAt(i));

if (string1.length() == string2.length()) { // Interleaving when string1 and string2 are equal length.

for (int j = 0; j < list1.size(); j++) {

result = result + list1.get(j);

result = result + list2.get(j);

}

return result;

}

if (string1.length() > string2.length()) { // Interleaving when string1 is longer than string2.

while (list2.size() > 0) {

result = result + list1.get(0);

list1.remove(0);

result = result + list2.get(0);

list2.remove(0);

}

for (char character : list1) { // Concatenate the rest of the characters in list1 to the result.

result = result + character;

}

return result;

}

if (string2.length() > string1.length()) { // Interleaving when string2 is longer than string1.

while (list1.size() > 0) {

result = result + list1.get(0);

list1.remove(0);

result = result + list2.get(0);

list2.remove(0);

}

for (char character : list2) { // Concatenate the rest of the characters in list2 to the result.

result = result + character;

}

return result;

}

return result;

}

Java/src/main/java/com/string/Interleave.java at Development · ailvcheng/Java · GitHub

Expand file tree

Breadcrumbs

Interleave.java

Latest commit

History

Breadcrumbs

Interleave.java

File metadata and controls