斯威夫特：标准二进制数组搜索？ [英] Swift: Binary search for standard array?

问题描述

我有一个排序的数组和想要做的二进制搜索就可以了。

I have a sorted array and want to do binary search on it.

于是我问，如果事情是已经在诸如排序等雨燕库可用？或者是有一种影响无关版本？

So I'm asking if something is already available in Swift library like sort etc.? Or is there a type independend version available?

当然，我可以用我自己写的，但我想，以避免再次重蹈覆辙。

Of course I could write it by my own, but I like to avoid reinventing the wheel again.

推荐答案

答案在这里与提高（通用）

func binarySearch<T:Comparable>(inputArr:Array<T>, searchItem: T)->Int{
    var lowerIndex = 0;
    var upperIndex = inputArr.count - 1

    while (true) {
        var currentIndex = (lowerIndex + upperIndex)/2
        if(inputArr[currentIndex] == searchItem) {
            return currentIndex
        } else if (lowerIndex > upperIndex) {
            return -1
        } else {
            if (inputArr[currentIndex] > searchItem) {
                upperIndex = currentIndex - 1
            } else {
                lowerIndex = currentIndex + 1
            }
        }
    }
}

var myArray = [1,2,3,4,5,6,7,9,10];
var searchIndex = binarySearch(myArray,5);
if searchIndex != -1{
    println("Element found on index: \(searchIndex)");
}

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