Binary search

typescript/binary-search/README.md

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+# Binary Search
+
+Welcome to Binary Search on Exercism's TypeScript Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Implement a binary search algorithm.
+
+Searching a sorted collection is a common task. A dictionary is a sorted
+list of word definitions. Given a word, one can find its definition. A
+telephone book is a sorted list of people's names, addresses, and
+telephone numbers. Knowing someone's name allows one to quickly find
+their telephone number and address.
+
+If the list to be searched contains more than a few items (a dozen, say)
+a binary search will require far fewer comparisons than a linear search,
+but it imposes the requirement that the list be sorted.
+
+In computer science, a binary search or half-interval search algorithm
+finds the position of a specified input value (the search "key") within
+an array sorted by key value.
+
+In each step, the algorithm compares the search key value with the key
+value of the middle element of the array.
+
+If the keys match, then a matching element has been found and its index,
+or position, is returned.
+
+Otherwise, if the search key is less than the middle element's key, then
+the algorithm repeats its action on the sub-array to the left of the
+middle element or, if the search key is greater, on the sub-array to the
+right.
+
+If the remaining array to be searched is empty, then the key cannot be
+found in the array and a special "not found" indication is returned.
+
+A binary search halves the number of items to check with each iteration,
+so locating an item (or determining its absence) takes logarithmic time.
+A binary search is a dichotomic divide and conquer search algorithm.
+
+## Source
+
+### Created by
+
+- @anuragsoni
+
+### Contributed to by
+
+- @masters3d
+- @SleeplessByte
+
+### Based on
+
+Wikipedia - http://en.wikipedia.org/wiki/Binary_search_algorithm