# 37. implement Binary Search (unique)

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easy - accepted / - tried

Even in Front-End review, basic algorithm technique like Binary Search are likely to be asked.

You are given an **unique & ascending** array of integers, please search for its index with Binary Search.

If not found, return `-1`

*note*

Please don't use `Array.prototype.indexOf()`

, it is not our goal.

48. search first index with Binary Search(possible duplicate array) 49. search last index with Binary Search(possible duplicate array) 50. search element right before target with Binary Search(possible duplicate array) 51. search element right after target with Binary Search(possible duplicate array)