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Commitcfd4c0e

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add 247, 326, 242 bit manipulations
1 parent8508bc4 commitcfd4c0e

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4 files changed

+97
-0
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4 files changed

+97
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lines changed

‎Easy/326-powerOfThree.js‎

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/**
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*@param {number} n
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*@return {boolean}
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*/
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// recursive
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varisPowerOfThree=function(n){
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if(n===0)returnfalse;
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if(n===1)returntrue;
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returnn%3===0&&isPowerOfThree(Math.floor(n/3));
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};
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// iterative Ways
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varisPowerOfThree=function(n){
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if(n>1){
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while(n%3===0){
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n=Math.floor(n/3);
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}
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}
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returnn===1;
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};

‎Easy/342-powerOfFour.js‎

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/**
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*@param {number} num
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*@return {boolean}
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*/
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varisPowerOfFour=function(num){
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if(num>1){
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while(num%4===0){
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num=Math.floor(num/4);
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}
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}
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returnnum===1;
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};
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varisPowerOfFour=function(num){
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if(num>1){
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if((num&(num-1))===0){
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if((num-1)%3===0){
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returntrue;
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}
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}
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}
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returnnum===1;
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};
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// the '1' bit only appears at odd bit, so if any every 3 bits (=5) has 1, it is
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// a number of power of 4
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varisPowerOfFour=function(num){
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if(num>1){
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if((num&(num-1))===0){
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if((num&0x55555555)!==0){
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returntrue;
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}
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}
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}
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returnnum===1;
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};

‎Medium/247-topKFrequentElements.js‎

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/**
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* Solution: 1. priority queue, O(n*log(k)), however JavaScript doesn't natively support heap
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* 2. bucket sort
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*
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*@param {number[]} nums
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*@param {number} k
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*@return {number[]}
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*/
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vartopKFrequent=function(nums,k){
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varmap={};
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for(vari=0;i<nums.length;i++){
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if(map.hasOwnProperty(nums[i])){
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map[nums[i]]+=1;
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}else{
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map[nums[i]]=1;
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}
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}
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varbucket=[];
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for(varkeyinmap){
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varkeyVal=parseInt(key,10);
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bucket[map[key]] ?bucket[map[key]].push(keyVal) :bucket[map[key]]=[keyVal];
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}
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varresult=[];
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for(varj=bucket.length-1;j>0;j--){
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if(bucket[j]){
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result=result.concat(bucket[j]);
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}
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if(result.length>=k)break;
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}
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returnresult;
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};

‎README.md‎

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*[290. Word Pattern](https://leetcode.com/problems/word-pattern/) -[Solution](./Easy/290-wordPattern.js)
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*[299. Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/) -[Solution](./Easy/299-bullsandCows.js)
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*[303. Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/) -[Solution](./Easy/303-rangeSumQuery.js)
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*[326. Power of Three](https://leetcode.com/problems/power-of-three/) -[Solution](./Easy/326-powerOfThree.js)
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*[328. Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/) -[Solution](./Easy/328-oddevenLinkedList.js)
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*[342. Power of Four](https://leetcode.com/problems/power-of-four/) -[Solution](./Easy/342-powerOfFour.js)
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#####Medium
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*[1. Two Sum](https://leetcode.com/problems/two-sum/) -[Solution](./Medium/1-twoSum.js)
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*[318. Maximum Product of Word Lengths](https://leetcode.com/problems/maximum-product-of-word-lengths/) -[Solution](./Medium/318-maximumProductWordLengths.js)
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*[319. Bulb Switcher](https://leetcode.com/problems/bulb-switcher/) -[Solution](./Medium/319-bulbSwitcher.js)
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*[337. House Robber III](https://leetcode.com/problems/house-robber-iii/) -[Solution](./Medium/337-houseRobberIII.js)
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*[347. Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/) -[Solution](./Medium/247-topKFrequentElements.js)
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#####Hard
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*[23. Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/) -[Solution](./Hard/23-MergeKSortedLists.js)

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