HashTable : (First recurring char)
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//Google Question
//Given an array = [2,5,1,2,3,5,1,2,4]:
//It should return 2
//Given an array = [2,1,1,2,3,5,1,2,4]:
//It should return 1
//Given an array = [2,3,4,5]:
//It should return undefined
let array = [2,5,5,2]
//We will learn more about time complaxcity of below code like what is TC for map.has() methos
function firstRecurringCharacter(input) {
let map = new Map();
for(let i=0;i<input.length;i++){
if(map.has(input[i])){
return input[i]
}else{
map.set(input[i],true)
}
}
return undefined
}
let data = firstRecurringCharacter(array)
console.log(data)
//we can do above thing even without using map methods.
function firstRecuringCharWithSimpleObj(input){
let map = {}
for(let i = 0; i < input.length ; i++){
if(map[input[i]] !== undefined){
return input[i];
}else {
map[input[i]] = true
}
}
return undefined
}
let mapObjSolution = firstRecuringCharWithSimpleObj([2,5,2])
console.log(mapObjSolution)
// Find count of all recurring count
function findAllRecurringCount(input) {
let map = new Map();
console.log(input)
for(let i=0;i<input.length;i++){
if(map.has(input[i])){
map.set(input[i],map.get(input[i])+1)
}else{
map.set(input[i],1)
}
}
return map;
}
let mapRecurring = findAllRecurringCount(array)
console.log(mapRecurring)
/// First recuring multi loop solution
/*
* In case of multiple loops always means always thing about from where we need to start loop not always from zero bhai
*/
function firstRecuring(input){
let maxDiff = Infinity
let val = Infinity
for(let i = 0 ; i < input.length ;i++){
for(let j = i+1; j < input.length ; j++){
if(input[i] === input[j]){
let currentDiff = j - i;
if(currentDiff < maxDiff){
maxDiff = currentDiff;
val = input[j]
}
}
}
}
return val
}
console.log(firstRecuring([2,5,5,2]))
// Good things about hashmap : Fast lookups,Fast Inserts and Flexible Keys
// Bad things about hashmaps : unordered , slow key iteration
JavaScript
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