solves #68: Text Justification in java

Author: anishLearnsToCode

README.md

@@ -68,6 +68,7 @@
 |  64  | [Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum)                                                                                                     |                                                          [![Java](assets/java.png)](src/MinimumPathSum.java) [![Python](assets/python.png)](python/minimum_path_sum.py)                                                          |                                                                                                                                   |
 |  66  | [Plus One](https://leetcode.com/problems/plus-one)                                                                                                                     |                                                                 [![Java](assets/java.png)](src/PlusOne.java) [![Python](assets/python.png)](python/plus_one.py)                                                                  |                                                                                                                                   |
 |  67  | [Add Binary](https://leetcode.com/problems/add-binary)                                                                                                                 |                                                               [![Java](assets/java.png)](src/AddBinary.java) [![Python](assets/python.png)](python/add_binary.py)                                                                |                                                                                                                                   |
+|  68  | [Text Justification](https://leetcode.com/problems/text-justification)                                                                                                 |                                                                                          [![Java](assets/java.png)](src/AddBinary.java)                                                                                          |                                                                                                                                   |
 |  69  | [Sqrt(x)](https://leetcode.com/problems/sqrtx)                                                                                                                         |                                                                    [![Java](assets/java.png)](src/Sqrtx.java) [![Python](assets/python.png)](python/sqrt.py)                                                                     |                                                                                                                                   |
 |  70  | [Climbing Stairs](https://leetcode.com/problems/climbing-stairs)                                                                                                       |                                                          [![Java](assets/java.png)](src/ClimbingStairs.java) [![Python](assets/python.png)](python/climbing_stairs.py)                                                           |                                                                                                                                   |
 |  71  | [Simplify Path](https://leetcode.com/problems/simplify-path)                                                                                                           |                                                                                        [![Java](assets/java.png)](src/SimplifyPath.java)                                                                                         |                                                                                                                                   |

src/HelloWorld.java

@@ -1,19 +1,27 @@
 public class HelloWorld {
-    public int lengthOfLastWord(String s) {
-        int i = s.length() - 1;
+    public int strStr(String haystack, String needle) {
+        if (needle.length() > haystack.length()) {
+            return -1;
+        }
 
-        // skip all spaces at the end of the word
-        while (i >= 0 && s.charAt(i) == ' ') {
-            i--;
+        for (int i = 0 ; i < haystack.length() ; i++) {
+            if (needle.charAt(0) == haystack.charAt(i) && containsAt(haystack, needle, i)) {
+                return i;
+            }
         }
 
-        final int wordEndIndex = i;
+        return -1;
+    }
 
-        // arrive at the start of the word
-        while (i >= 0 && s.charAt(i) != ' ') {
-            i--;
+    private static boolean containsAt(String haystack, String needle, int i) {
+        if (needle.length() > haystack.length() - i) {
+            return false;
         }
-
-        return wordEndIndex - i;
+        for (int index = i + 1 ; index < haystack.length() && index - i < needle.length() ; index++) {
+            if (needle.charAt(index - i) != haystack.charAt(index)) {
+                return false;
+            }
+        }
+        return true;
     }
 }

src/LongestCommonPrefix.java

@@ -1,4 +1,6 @@
-// https://leetcode.com/problems/longest-common-prefix/
+// https://leetcode.com/problems/longest-common-prefix
+// T: O(|array| * |array[i]|)
+// S: O(|array[i]|)
 
 public class LongestCommonPrefix {
     public String longestCommonPrefix(String[] array) {

src/TextJustification.java

@@ -0,0 +1,66 @@
+// https://leetcode.com/problems/text-justification
+// T: O(|words|)
+// S: O(|words|)
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TextJustification {
+    public List<String> fullJustify(String[] words, int maxWidth) {
+        List<String> ans = new ArrayList<>();
+        int i = 0;
+
+        while (i < words.length) {
+            List<String> currentLine = getWords(i, words, maxWidth);
+            i += currentLine.size();
+            ans.add(createLine(currentLine, i, words, maxWidth));
+        }
+
+        return ans;
+    }
+
+    private List<String> getWords(int i, String[] words, int maxWidth) {
+        List<String> currentLine = new ArrayList<>();
+        int currLength = 0;
+
+        while (i < words.length && currLength + words[i].length() <= maxWidth) {
+            currentLine.add(words[i]);
+            currLength += words[i].length() + 1;
+            i++;
+        }
+
+        return currentLine;
+    }
+
+    private String createLine(
+            List<String> line,
+            int i,
+            String[] words,
+            int maxWidth
+    ) {
+        int baseLength = -1;
+        for (String word : line) {
+            baseLength += word.length() + 1;
+        }
+
+        int extraSpaces = maxWidth - baseLength;
+
+        if (line.size() == 1 || i == words.length) {
+            return String.join(" ", line) + " ".repeat(extraSpaces);
+        }
+
+        int wordCount = line.size() - 1;
+        int spacesPerWord = extraSpaces / wordCount;
+        int needsExtraSpace = extraSpaces % wordCount;
+
+        for (int j = 0; j < needsExtraSpace; j++) {
+            line.set(j, line.get(j) + " ");
+        }
+
+        for (int j = 0; j < wordCount; j++) {
+            line.set(j, line.get(j) + " ".repeat(spacesPerWord));
+        }
+
+        return String.join(" ", line);
+    }
+}