solved: Text Justification

Author: lambiengcode

README.md

@@ -515,4 +515,68 @@ bool isNumber(String s) {
 
   return num.tryParse(s) != null;
 }
+```
+
+### Text Justification
+
+```dart
+List<String> fullJustify(List<String> words, int maxWidth) {
+  final List<String> result = [];
+  String temp = '';
+
+  for (int index = 0; index < words.length; index++) {
+    final String word = words[index];
+
+    if (temp.length + word.length + (temp.isEmpty ? 0 : 1) <= maxWidth) {
+      temp += '${temp.isEmpty ? '' : ' '}$word';
+    } else {
+      if (temp.trim().isNotEmpty) {
+        result.add(temp.trim());
+      }
+      temp = word;
+    }
+
+    if (index == words.length - 1 && temp.isNotEmpty) {
+      result.add(temp.trim());
+    }
+  }
+
+  return fillSpace(result, maxWidth);
+}
+
+List<String> fillSpace(List<String> words, int maxWidth) {
+  for (int i = 0; i < words.length; i++) {
+    final String word = words[i];
+    if (word.length < maxWidth) {
+      final List<String> splits = word.split(' ');
+      if (splits.length < 2 || i == words.length - 1) {
+        words[i] =
+            word + List.generate(maxWidth - word.length, (index) => ' ').join();
+      } else {
+        int leftSpace = maxWidth - word.length + splits.length - 1;
+        String temp = '';
+
+        for (int j = 0; j < splits.length; j++) {
+          final double div = leftSpace / (splits.length - j);
+          int avgSpace = div.round();
+          if (leftSpace / avgSpace > 0) {
+            avgSpace = div.ceil();
+          }
+
+          if (j == 0) {
+            temp += splits[j];
+          } else if (leftSpace > 0) {
+            final int cal = leftSpace < avgSpace ? leftSpace : avgSpace;
+            temp += '${List.generate(cal, (index) => ' ').join()}${splits[j]}';
+            leftSpace -= cal;
+          }
+        }
+
+        words[i] = temp;
+      }
+    }
+  }
+
+  return words;
+}
 ```

src/text_justification.dart

@@ -0,0 +1,180 @@
+void main(List<String> args) {
+  List<List> cases = [
+    [
+      ["This", "is", "an", "example", "of", "text", "justification."],
+      16,
+    ],
+    [
+      ["a", "b", "c", "d", "e"],
+      3
+    ],
+    [
+      ["Listen", "to", "many,", "speak", "to", "a", "few."],
+      6,
+    ],
+    [
+      [
+        "ask",
+        "not",
+        "what",
+        "your",
+        "country",
+        "can",
+        "do",
+        "for",
+        "you",
+        "ask",
+        "what",
+        "you",
+        "can",
+        "do",
+        "for",
+        "your",
+        "country"
+      ],
+      16,
+    ],
+    [
+      [
+        "Give",
+        "me",
+        "my",
+        "Romeo;",
+        "and,",
+        "when",
+        "he",
+        "shall",
+        "die,",
+        "Take",
+        "him",
+        "and",
+        "cut",
+        "him",
+        "out",
+        "in",
+        "little",
+        "stars,",
+        "And",
+        "he",
+        "will",
+        "make",
+        "the",
+        "face",
+        "of",
+        "heaven",
+        "so",
+        "fine",
+        "That",
+        "all",
+        "the",
+        "world",
+        "will",
+        "be",
+        "in",
+        "love",
+        "with",
+        "night",
+        "And",
+        "pay",
+        "no",
+        "worship",
+        "to",
+        "the",
+        "garish",
+        "sun."
+      ],
+      25
+    ],
+    [
+      ["What", "must", "be", "acknowledgment", "shall", "be"],
+      16,
+    ],
+    [
+      [
+        "Science",
+        "is",
+        "what",
+        "we",
+        "understand",
+        "well",
+        "enough",
+        "to",
+        "explain",
+        "to",
+        "a",
+        "computer.",
+        "Art",
+        "is",
+        "everything",
+        "else",
+        "we",
+        "do"
+      ],
+      20,
+    ]
+  ];
+
+  for (final testcase in cases) {
+    print(fullJustify(testcase.first, testcase.last));
+  }
+}
+
+List<String> fullJustify(List<String> words, int maxWidth) {
+  final List<String> result = [];
+  String temp = '';
+
+  for (int index = 0; index < words.length; index++) {
+    final String word = words[index];
+
+    if (temp.length + word.length + (temp.isEmpty ? 0 : 1) <= maxWidth) {
+      temp += '${temp.isEmpty ? '' : ' '}$word';
+    } else {
+      if (temp.trim().isNotEmpty) {
+        result.add(temp.trim());
+      }
+      temp = word;
+    }
+
+    if (index == words.length - 1 && temp.isNotEmpty) {
+      result.add(temp.trim());
+    }
+  }
+
+  return fillSpace(result, maxWidth);
+}
+
+List<String> fillSpace(List<String> words, int maxWidth) {
+  for (int i = 0; i < words.length; i++) {
+    final String word = words[i];
+    if (word.length < maxWidth) {
+      final List<String> splits = word.split(' ');
+      if (splits.length < 2 || i == words.length - 1) {
+        words[i] =
+            word + List.generate(maxWidth - word.length, (index) => ' ').join();
+      } else {
+        int leftSpace = maxWidth - word.length + splits.length - 1;
+        String temp = '';
+
+        for (int j = 0; j < splits.length; j++) {
+          final double div = leftSpace / (splits.length - j);
+          int avgSpace = div.round();
+          if (leftSpace / avgSpace > 0) {
+            avgSpace = div.ceil();
+          }
+
+          if (j == 0) {
+            temp += splits[j];
+          } else if (leftSpace > 0) {
+            final int cal = leftSpace < avgSpace ? leftSpace : avgSpace;
+            temp += '${List.generate(cal, (index) => ' ').join()}${splits[j]}';
+            leftSpace -= cal;
+          }
+        }
+
+        words[i] = temp;
+      }
+    }
+  }
+
+  return words;
+}