Huangzj
53 lines
1.0 KiB
Go
53 lines
1.0 KiB
Go
/*
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* @Author : huangzj
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* @Time : 2020/8/18 17:45
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* @Description：二分查找法，对于有序数组进行查找
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*/
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package search
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func BinarySearch(list []int, value int) int {
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low := 0
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high := len(list) - 1
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var mid int
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for low <= high {
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mid = (low + high) >> 1 //相当于(low + high) / 2
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if value == list[mid] {
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return mid
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}
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if value < list[mid] {
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high = mid - 1
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} else {
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low = mid + 1
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}
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}
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return -1
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}
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//二分查找在两个数值之间的数据
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func BinarySearchBetween(list []int, value int) int {
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low := 0
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high := len(list) - 1
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var mid int
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for low <= high {
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//求mid
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mid = (low + high) >> 1
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//要算后面一个元素，所以下标要判断是否超过 并且需要考虑超过数组最大值的情况
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if (mid+1 < len(list) && value > list[mid] && value < list[mid+1]) || value == list[mid] || (mid+1 >= len(list) && value > list[mid]) {
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return mid
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}
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//位移
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if value < list[mid] {
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high = mid - 1
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} else {
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low = mid + 1
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}
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}
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//未找到元素
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return -1
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}
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