sherlock-and-anagrams.js

/*
 *
 *  ------------------------
 * |  SHERLOCK AND ANAGRAMS |
 *  ------------------------
 *
 *
 *
 * Two strings are anagrams of each other if the 
 * letters of one string can be rearranged to form 
 * the other string. given a string, find the number of pairs 
 * of substrings of the string that are anagrams of each other.
 * It must return an integer that represents the number 
 * of anagrammatic pairs of substrings 
 *
 *
 *
 * e.g.
 * 
 * function sherlockAndAnagrams(s) { // s = "abba"
 *      // should return 4 --> ["a","a"], ["b","b"], ["ab", "ba"], ["abb", "bba"]
 * }
 *
 *
 * */


/*
 *
 * ***** SOLUTION
 *
 * */


function sherlockAndAnagrams(s) {
    // initialize anagramMap
    // initialize range
    // initialize anagramCounter
    const anagramMap = {};
    let range = 1;
    let anagramCounter = 0;

    // while loop until range is === s.length
    while(range < s.length){
        // populate map using for loop
        for(let i = 0; i < s.length; i++){
            if(s[(i + range) - 1]){
                const key = s.slice(i, i + range).split("").sort().join("");
                    //console.log("range", `${i} - ${i + range} : ${key}`);
                anagramMap[key] = anagramMap[key] + 1 || 1;
            };
        };
        range ++;
    };
    // loop over anagram and find all keys that have values of greater than 1
    // increase counter if they are
    for(let key in anagramMap) {
        const value = anagramMap[key];
        if(value === 2) {
            anagramCounter++;
        }
        if(value > 2) {
            for(let i = 0; i < value; i++) {
                for(let j = i + 1; j < value; j++) {
                    anagramCounter ++;
                }
            };
        }
    };
    return anagramCounter;
}



/*
 *
 * ***** TESTS
 *
 * */



const s1 = "kkkk"; // 10 
const s2 = "abba"; // 4
const s3 = "yuyuyyu";
const s4 = "osjfdlkksjf";

console.log("s1 --- ", sherlockAndAnagrams(s1));
console.log("s2 --- ", sherlockAndAnagrams(s2));
//console.log("s3 --- ", sherlockAndAnagrams(s3));
//console.log("s4 --- ", sherlockAndAnagrams(s4));