Related Articles
Justify the given Text based on the given width of each line
• Difficulty Level : Expert
• Last Updated : 27 Feb, 2020

Given a string str and width of each line as L, the task is to justify the string such that each line of justified text is of length L with help of space (‘ ‘) and the last line should be left-justified.

Examples:

Input: str = “GeeksforGeek is the best computer science portal for geeks.”, L = 16
Output:
GeeksforGeek__is
the_________best
computer_science
portal_______for
geeks.__________

Input: str = “The quick brown fox jumps over the lazy dog.”, L = 11
Output:
The___quick
brown___fox
jumped_over
the____lazy
dogs.______
The symbol _ denotes a space.

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:
The number of spaces between words in each line cannot be computed until a complete set of words in that line is known. We will solve this problem on a line-by-line basis.

1. Split the given text into words
2. Firstly select the words which can be inserted in each line including a space between each word. For that, the sum of length of included words with one space between them must be smaller than or equal to L.
3. Now count the number of spaces needed to make the length of each line L and distribute the spaces evenly.
4. Repeat above steps for next set of words.
5. For the last line spaces must be assigned at the end as the last line must be left-justified.

Below is the implementation of the above approach:

 `// C++ program to Justify the given Text``// according to the given width of each line`` ` `#include "bits/stdc++.h"``using` `namespace` `std;`` ` `// Function to join the words``// with spaces spread evenly``string JoinALineWithSpace(``    ``vector& words,``    ``int` `start, ``int` `end,``    ``int` `num_spaces)``{`` ` `    ``// Number of words in current line``    ``int` `num_words_curr_line``        ``= end - start + 1;`` ` `    ``// String to store the justified text``    ``string line;`` ` `    ``for` `(``int` `i = start; i < end; i++) {`` ` `        ``line += words[i];``        ``--num_words_curr_line;`` ` `        ``// Count number of current space needed``        ``int` `num_curr_space``            ``= ``ceil``((``double``)(num_spaces)``                   ``/ num_words_curr_line);`` ` `        ``// Insert spaces in string line``        ``line.append(num_curr_space, ``' '``);`` ` `        ``// Delete the spaces inserted in line``        ``num_spaces -= num_curr_space;``    ``}`` ` `    ``// Insert word to string line``    ``line += words[end];``    ``line.append(num_spaces, ``' '``);`` ` `    ``// Return justified text``    ``return` `line;``}`` ` `// Function that justify the words of``// sentence of length of line L``vector JustifyText(``    ``vector& words,``    ``int` `L)``{`` ` `    ``int` `curr_line_start = 0;``    ``int` `num_words_curr_line = 0;``    ``int` `curr_line_length = 0;`` ` `    ``// To store the justified text``    ``vector result;`` ` `    ``// Traversing the words array``    ``for` `(``int` `i = 0; i < words.size(); i++) {`` ` `        ``// curr_line_start is the first word``        ``// in the current line, and i is``        ``// used to identify the last word``        ``++num_words_curr_line;`` ` `        ``int` `lookahead_line_length``            ``= curr_line_length``              ``+ words[i].size()``              ``+ (num_words_curr_line - 1);`` ` `        ``// If by including the words length becomes L,``        ``// then that set of words is justified``        ``// and add the justified text to result``        ``if` `(lookahead_line_length == L) {`` ` `            ``// Justify the set of words``            ``string ans``                ``= JoinALineWithSpace(``                    ``words,``                    ``curr_line_start,``                    ``i,``                    ``i - curr_line_start);`` ` `            ``// Store the justified text in result``            ``result.emplace_back(ans);`` ` `            ``// Start the current line``            ``// with next index``            ``curr_line_start = i + 1;`` ` `            ``// num of words in the current line``            ``// and current line length set to 0``            ``num_words_curr_line = 0;``            ``curr_line_length = 0;``        ``}`` ` `        ``// If by including the words such that``        ``// length of words becomes greater than L,``        ``// then hat set is justified with``        ``// one less word and add the``        ``// justified text to result``        ``else` `if` `(lookahead_line_length > L) {`` ` `            ``// Justify the set of words``            ``string ans``                ``= JoinALineWithSpace(``                    ``words,``                    ``curr_line_start,``                    ``i - 1,``                    ``L - curr_line_length);`` ` `            ``// Store the justified text in result``            ``result.emplace_back(ans);`` ` `            ``// Current line set to current word``            ``curr_line_start = i;`` ` `            ``// Number of words set to 1``            ``num_words_curr_line = 1;`` ` `            ``// Current line length set``            ``// to current word length``            ``curr_line_length = words[i].size();``        ``}`` ` `        ``// If length is less than L then,``        ``// add the word to current line length``        ``else` `{``            ``curr_line_length``                ``+= words[i].size();``        ``}``    ``}`` ` `    ``// Last line is to be left-aligned``    ``if` `(num_words_curr_line > 0) {``        ``string line``            ``= JoinALineWithSpace(``                ``words,``                ``curr_line_start,``                ``words.size() - 1,``                ``num_words_curr_line - 1);`` ` `        ``line.append(``            ``L - curr_line_length``                ``- (num_words_curr_line - 1),``            ``' '``);`` ` `        ``// Insert the last line``        ``// left-aligned to result``        ``result.emplace_back(line);``    ``}`` ` `    ``// Return result``    ``return` `result;``}`` ` `// Function to insert words``// of sentence``vector splitWords(string str)``{`` ` `    ``vector words;``    ``string a = ``""``;``    ``for` `(``int` `i = 0; str[i]; i++) {`` ` `        ``// Add char to string a``        ``// to get the word``        ``if` `(str[i] != ``' '``) {``            ``a += str[i];``        ``}`` ` `        ``// If a space occurs``        ``// split the words and``        ``// add it to vector``        ``else` `{``            ``words.push_back(a);``            ``a = ``""``;``        ``}``    ``}`` ` `    ``// Push_back the last word``    ``// of sentence``    ``words.push_back(a);`` ` `    ``// Return the vector of``    ``// words extracted from``    ``// string``    ``return` `words;``}`` ` `// Function to print justified text``void` `printJustifiedText(vector& result)``{``    ``for` `(``auto``& it : result) {``        ``cout << it << endl;``    ``}``}`` ` `// Function to call the justification``void` `justifyTheText(string str, ``int` `L)``{`` ` `    ``vector words;`` ` `    ``// Inserting words from``    ``// given string``    ``words = splitWords(str);`` ` `    ``// Function call to``    ``// justify the text``    ``vector result``        ``= JustifyText(words, L);`` ` `    ``// Print the justified``    ``// text``    ``printJustifiedText(result);``}`` ` `// Driver Code``int` `main()``{``    ``string str``        ``= ``"GeeksforGeek is the best"``          ``" computer science portal"``          ``" for geeks."``;``    ``int` `L = 16;`` ` `    ``justifyTheText(str, L);`` ` `    ``return` `0;``}`
Output:
```GeeksforGeek  is
the         best
computer science
portal       for
geeks.
```

Time Complexity: O(N), where N = length of string

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up