Text Justification, C++ (gcc)

Text Justification

/* Text Justification
Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.

You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ' ' when necessary so that each line has exactly L characters.

Extra spaces between words should be distributed as evenly as possible. If the number of spaces on a line do not divide evenly between words, the empty slots on the left will be assigned more spaces than the slots on the right.

For the last line of text, it should be left justified and no extra space is inserted between words. */

#include <iostream>
#include <vector>
#include <string> 
using namespace std;

string getSpaces(int n){
    string s = "";
    for(int i=0; i<n;i++) s += " ";
    return s; 
}

string getLine(vector<string>& words, int start, int end, int letterCount, int maxWidth){
    string res = words[start];
    int spaces = maxWidth - letterCount;
    if(start == end){ // don't forget this corner case 
        res += getSpaces(spaces);
        return res;
    }
    int numOfSpace = spaces/(end-start);
    int extraOne = spaces%(end-start);
    string space0 = getSpaces(numOfSpace);
    string space1 = space0 + " "; 
    for(int i= 0; i< end-start; i++){
        res  = res + (i < extraOne? space1: space0) + words[start + 1 + i];
    }
    return res; 
}

vector<string> fullJustify(vector<string>& words, int maxWidth) {
    int N = words.size(); 
    int i = 0, j = 0; // for word counting 
    int counter = 0;  // letter counting 
    vector<string> res; 
    while(i<N && j<N){
        int len = words[j].length(); 
        counter += len;
        if(counter + j - i > maxWidth){
            counter -= len; 
            res.push_back(getLine(words, i, j-1, counter, maxWidth));
            i = j; 
            counter = 0; 
        }else{
            j++;
        }
    }
    // check the last session 
    if(counter){
        string last = words[i];
        for(int x=i+1; x < j; x++) last = last + " " + words[x];
        last = last + getSpaces(maxWidth - last.size());
        res.push_back(last);
    }

return res; 
}

int main(){
    vector<string> words = {"This", "is", "an", "example", "of", "text", "justification."}; 
    vector<string> lines = fullJustify(words, 16); 
    string s = "";
    for(int i=0; i<16; i++) s += char(i%10+'0');
    cout << "=>" << s << "<=" << endl;
    for(auto x: lines)
        cout << "=>" << x << "<=" << endl;
    
    return 0; 
}


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