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Commit 01ccda9

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add: Search for a Range
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‎README.md‎

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|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/) | [JavaScript](./src/remove-nth-node-from-end-of-list/res.js)|Medium|
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|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses/) | [JavaScript](./src/generate-parentheses/res.js)|Medium|
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|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/) | [JavaScript](./src/remove-duplicates-from-sorted-array/res.js)|Easy|
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|34|[Search for a Range](https://leetcode.com/problems/search-for-a-range/) | [JavaScript](./src/search-for-a-range/res.js)|Medium|
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|48|[Rotate Image](https://leetcode.com/problems/rotate-image/) | [JavaScript](./src/rotate-image/res.js)|Medium|
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|66|[Plus One](https://leetcode.com/problems/plus-one/) | [JavaScript](./src/plus-one/res.js)|Easy|
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|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/) | [JavaScript](./src/sqrtx/res.js)|Easy|

‎src/search-for-a-range/res.js‎

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// Given an array of integers sorted in ascending order, find the starting and ending position of a given target value.
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// Your algorithm's runtime complexity must be in the order of O(log n).
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// If the target is not found in the array, return [-1, -1].
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// For example,
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// Given [5, 7, 7, 8, 8, 10] and target value 8,
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// return [3, 4].
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/**
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* res.js
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* @authors Joe Jiang (hijiangtao@gmail.com)
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* @date 2017年02月26日 22:56:22
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* @version $Id$
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*
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* @param {number[]} nums
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* @param {number} target
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* @return {number[]}
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*/
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let searchRange = function(nums, target) {
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let arrlen = nums.length;
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if (!arrlen) {
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return [-1, -1];
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}
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let leftIndex = binarySearch(nums, 0, arrlen-1, target, 'l'), rightIndex;
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if (leftIndex === -1) {
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return [-1, -1];
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} else {
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rightIndex = binarySearch(nums, leftIndex, arrlen-1, target, 'r');
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}
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return [leftIndex, rightIndex];
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};
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let binarySearch = function(nums, begin, end, target, type) {
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let arrlen = nums.length;
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while (begin <= end) {
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let mid = begin + Number.parseInt( (end-begin)/2 ),
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midVal = nums[mid];
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if (midVal === target) {
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switch (type) {
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case 'l':
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if (mid === 0 || nums[mid-1] !== target) {
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return mid;
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} else {
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end = mid-1;
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}
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break;
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default:
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if (mid === arrlen-1 || nums[mid+1] !== target) {
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return mid;
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} else {
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begin = mid+1;
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}
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break;
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}
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} else if (midVal > target) {
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end = mid-1;
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} else if (midVal < target) {
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begin = mid+1;
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}
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}
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return -1;
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};

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