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Commit d62e62c

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Merge pull request knaxus#207 from Ahtaxam/master
Add 3-sum problem with improvement issue knaxus#208 
2 parents 56fb83e + 75a9df6 commit d62e62c

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‎TOC.md

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- [Next Greater for Every Element in an Array](src/_Problems_/next-greater-element)
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- [Compose Largest Number](src/_Problems_/compose-largest-number)
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- [Rotate Image](src/_Problems_/rotate-image)
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-[3 Sum](src/_Problems_/3Sum/)
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### Searching
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- [Binary Search](src/_Searching_/BinarySearch)

‎src/_Problems_/3Sum/3sum.js

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const threeSum = function(nums) {
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// sort the array
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nums = nums.sort((a, b) => a - b);
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let result = [];
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// iterate through the array and use two pointers to find the sum
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for (let i = 0; i < nums.length; ++i) {
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let left = i + 1;
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let right = nums.length - 1;
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while (left < right) {
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let sum = nums[i] + nums[left] + nums[right];
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if (sum == 0) {
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result.push([nums[i], nums[left], nums[right]]);
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left++;
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right--;
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}
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else if (sum < 0) {
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left++;
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}
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else {
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right--;
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}
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}
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// skip duplicates
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while (i < nums.length - 1 && nums[i] == nums[i + 1]) {
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i++;
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}
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}
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// initialize set to remove duplicate
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const set = new Set(result.map(JSON.stringify));
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// final output array
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output = (new Array(...set).map(JSON.parse));
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return output;
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};
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module.exports = threeSum;
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‎src/_Problems_/3Sum/3sum.test.js

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const threeSum = require("./3sum");
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describe("threeSum", () => {
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it("Should return [[-1, -1, 2], [-1, 0, 1]]", () => {
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expect(threeSum([-1, 0, 1, 2, -1, -4])).toEqual([
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[-1, -1, 2],
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[-1, 0, 1],
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]);
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});
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it("Should return [[0, 0, 0]]", () => {
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expect(threeSum([0, 0, 0])).toEqual([[0, 0, 0]]);
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});
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it("Should return [[-1, -1, 2]]", () => {
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expect(threeSum([-1, 2, -1, -4])).toEqual([[-1, -1, 2]]);
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});
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});

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