C++ 二分查找

已知一个排序数组A，如A=[-1,2,5,20,90,100,207,800]
另外一个乱序数组B，如B=[50,90,3,-1,207,80]
求B中的任意某个元素，是否在A中出现，出现用1代表，未出现用0代表。

用递归法二分查找：

#include<vector>
bool binary_search(std::vector<int> &sort_array, int begin, int end, int target)
{
 if (begin>end)
 {
  return false;
 }
 int mid = (begin + end) / 2;
 if (target==sort_array[mid])
 {
  return true;
 }
 else if (target<sort_array[mid])
 {
  return binary_search(sort_array, begin, mid-1, target);
 }
 else if (target>sort_array[mid])
 {
  return binary_search(sort_array, mid + 1, end, target);
 }
}
int main()
{
 int A[] = { -1,2,5,20,90,100,207,800 };
 int B[] = {50,90,3,-1,207,80};
 std::vector<int> sort_array;
 std::vector<int> random_array;
 for (int i = 0; i < sizeof(A)/sizeof(A[0]); i++)
 {
  sort_array.push_back(A[i]);
 }
 for (int i = 0; i < sizeof(B)/sizeof(B[0]); i++)
 {
  random_array.push_back(B[i]);
 }
 for (int i = 0; i < random_array.size(); i++)
 {
  bool C = binary_search(sort_array, 0, sort_array.size(), random_array[i]);
  printf("%d\n",C );
 }
 }

运行结果：
0
1
0
1
1
0

用循环法二分查找：

#include<vector>
bool binary_search(std::vector<int> &sort_array, int target)
{
 int begin = 0;
 int end = sort_array.size() - 1;
 while (begin<=end)
 {
  int mid = (begin + end) / 2;
  if (target==sort_array[mid])
  {
   return true;
  }
  else if (target<sort_array[mid])
  {
   end = mid - 1;
  }
  else if (target>sort_array[mid])
  {
   begin = mid + 1;
  }
 }
 return false;
}
std::vector<int> search_array(std::vector<int> &sort_array, std::vector<int> & random_array)
{
 std::vector<int> result;
 for (int i = 0; i < random_array.size(); i++)
 {
  int res=binary_search(sort_array, random_array[i]);
  result.push_back(res);
 }
 return result;
}
int main()
{
 int A[] = { -1,2,5,20,90,100,207,800 };
 int B[] = { 50,90,3,-1,207,80 };
 std::vector<int> sort_array;
 std::vector<int> random_array;
 std::vector<int> C;
 for (int i = 0; i < sizeof(A) / sizeof(A[0]); i++)
 {
  sort_array.push_back(A[i]);
 }
 for (int i = 0; i < sizeof(B) / sizeof(B[0]); i++)
 {
  random_array.push_back(B[i]);
 }
 C = search_array(sort_array, random_array);
 for (int i = 0; i < C.size(); i++)
 {
  printf("%d\n",C[i]);
 }
 return 0;
}

运行结果为:

0
1
0
1
1
0