add max char and int reverse

Author: Connor Leech

udemy-interview-bootcamp-course/README.md

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+# The Coding Interview Bootcamp: Algorithms + Data Structures
+
+
+Udemy course link: [The Coding Interview Bootcamp: Algorithms + Data Structures](https://www.udemy.com/coding-interview-bootcamp-algorithms-and-data-structure)
+
+[Source code](https://github.com/StephenGrider/algocasts) for the lessons.
+

udemy-interview-bootcamp-course/integer_reversal.js

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+
+// reverseInteger(500) === 5
+// reverseInteger(981) === 189
+// reverseInteger(-15) === -51
+// reverseInteger(-90) === -9
+
+function reverseInteger(integer) {
+	let isNegative = false;
+
+	if(integer < 0) isNegative = true;
+
+	const reversed = String(integer).split('').reverse().join('');
+
+	return (isNegative) ? parseInt(`-${reversed}`) : parseInt(`${reversed}`);
+}
+
+
+
+// You can use Math.sign to determine the +/- of a number
+// (could use reverse function as above)
+
+function reverseIntegerSolution(integer){
+	const reversed = integer.toString().split('').reduce((current, accum)=>{
+		return accum + current;
+	}, '');
+
+	return Math.sign(integer) * parseInt(reversed);
+}
+
+console.log(reverseIntegerSolution(-15));

udemy-interview-bootcamp-course/max_chars.js

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+// --- Directions
+// Given a string, return the character that is most
+// commonly used in the string.
+// --- Examples
+// maxChar("abcccccccd") === "c"
+// maxChar("apple 1231111") === "1"
+
+function maxChar(str) {
+	let map      = {};
+	let maxCount = 0;
+	let letter;
+
+	str.split('').forEach((letter)=>{
+		map[letter] = (map[letter]) ? map[letter] + 1 : 1;
+	});
+
+	for(key in map){
+		if(map[key] > maxCount){
+			maxCount = map[key];
+			letter   = key;
+		}
+		
+	}
+
+	return letter;
+}
+
+
+
+function maxCharSolution(str){
+	const charMap = {};
+	let max       = 0;
+	let maxChar   = '';
+
+	for(let char of str) {
+		if(charMap[char]){
+			charMap[char]++;
+		} else {
+			charMap[char] = 1;
+		}
+	}
+
+	for(char in charMap){
+		if(charMap[char] > max){
+			max     = charMap[char];
+			maxChar = char;
+		}
+	}
+
+	return maxChar;
+}
+
+console.log(maxCharSolution("abcccccccd"));
+
+
+/******************
+Most common string questions:
+
+- What is the most common character in this string?
+- Does string A have the same characters as string B? (anagram)
+- Does the string have any repeating characters in it?
+******************/