二分查找、二叉搜索

查找——折半查找（二分查找、二叉搜索）

简单的折半查找方法

public static int binSearch(int[] arr, int first ,int last, int target)
{
int mid;
int midValue;
while(first < last){
mid = (first + last) / 2;
midValue = arr[mid];//查找成功
if(target == midValue){
return mid;
}else if(target < midValue){
last = mid;
}else{
first = mid;
}
}
return -1;//查找失败
}

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泛型二叉搜索方法

public static <T> extends Comparable<? super T>

int binSearch(T[] arr, int first, int last, T target)
{
int mid;
T midValue;
while(first < last){
mid = (first + last) / 2;
midValue = arr[mid];
if(target.compareTo(midValue) == 0){
return mid; //查找成功
}else if(target.compareTo(midValue) < 0){
last = mid;
}else{
first = mid;
}
}
return -1; // 查找失败

}

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