Rearrange Spaces Between Words.java

// Runtime: 3 ms (Top 61.66%) | Memory: 40.5 MB (Top 92.33%)
class Solution {
    public String reorderSpaces(String text) {
        int spaces = 0;

        //count the spacex
        for(char c: text.toCharArray()){
            if(c==' ')
                spaces++;
        }

        //form word array
        String[] words = text.trim().split("\\s+");
        int nWords = words.length;

        StringBuilder sb = new StringBuilder();
        int spacesToApply=0,extraSpaces=0;

        //if there is only 1 word, then all spaces will be at the end
        if(nWords == 1){
            extraSpaces=spaces;
        }

        //if there are multiple words, find the spaces to apply between words and also any extra space
        else{
            spacesToApply = spaces / (nWords-1);
            extraSpaces = spaces % (nWords-1);
        }

        //append every word and then apply spaces
        for(int i=0;i<words.length-1;i++){
            sb.append(words[i]);

            for(int j=0;j<spacesToApply;j++)
                sb.append(" ");
        }

        //now append last word separately, bcz we dont want to apply spaces after last word
        sb.append(words[nWords-1]);

        //if there are any extra spaces that cannot be distributed among words, add them here
        for(int j=0;j<extraSpaces;j++)
                sb.append(" ");

        return sb.toString();
    }
}