add binary serach

Author: stone

.gitignore

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+.idea/

main

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+package main
+
+import "algorithm/search"
+
+func main() {
+	search.Use()
+}

main.go

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+package search
+
+import (
+	"bufio"
+	"fmt"
+	"learn_go/algorithm"
+	"os"
+	"sort"
+	"strconv"
+)
+
+func BinarySearch(key int, a []int) int {
+	lo := 0
+	hi := len(a) - 1
+	for {
+		if lo > hi {
+			break
+		}
+		mid := lo + (hi - lo) / 2
+		if key < a[mid] {
+			hi = mid - 1
+		} else if key > a[mid] {
+			lo = mid + 1
+		}else{
+			return mid
+		}
+	}
+	return -1
+}
+
+func Use()  {
+	scanner := bufio.NewScanner(os.Stdin)
+	var whiteList []int
+	for scanner.Scan(){
+		if s, err := strconv.Atoi(scanner.Text()); err == nil{
+			whiteList = append(whiteList, s)
+		}
+	}
+	sort.Ints(whiteList)
+	fmt.Println(algorithm.BinarySearch(30, whiteList))
+
+}
+

search/BinarySearch.go

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