在 C++ STL 中使用 binary_search()函数搜索字符串

用于搜索给定字符串的内置 STL 库函数binary_search()是否存在于给定字符串数组中。二分搜索是一种分而治之的方法。二分搜索算法背后的想法是将数组一分为二，直到找到元素，或者所有元素都用尽。将数组的中间项与目标值即需要搜索的值进行比较，如果匹配则返回true，否则如果中间项大于目标，则在左子数组中进行搜索。如果中间项小于目标，则在右子数组中执行搜索。

例子：

Input: arr[] = {“Geeks”, “For”, “GeeksForGeek”}
Search “Geeks”
Output: String Founded in array

句法：

binary_search(starting_address, ending_address, value_of_string)

下面是上述方法的实现：

C++14

// C++ program to implement Binary
// Search in Standard Template Library (STL)
#include 
#include 
using namespace std;
 
void show_array(string arr[], int arraysize)
{
    for (int i = 0; i < arraysize; i++)
        cout << arr[i] << ", ";
}
 
void binarySearch(string arr[], int size)
{
    cout << "\nThe array is : \n";
    show_array(arr, size);
 
    // Sort string array a for binary search as prerequisite
    sort(arr, arr + size);
 
    // Finding for "Geeks"
    cout << "\n\nSearching Result for \"Geeks\"";
    if (binary_search(arr, arr + size, "Geeks"))
        cout << "\nString Founded in array\n";
    else
        cout << "\nString not Founded in array\n";
 
    // Finding for string str
    string str = "Best";
    cout << "\nSearching Result for \"Best\"";
    if (binary_search(arr, arr + size, str))
        cout << "\nString Found in array";
    else
        cout << "\nString not Found in array";
}
 
// Driver code
int main()
{
    // Initialising string array a
    string arr[] = { "Geeks", "For", "GeeksForGeek" };
 
    // Find size of array arr
    int size = sizeof(arr) / sizeof(arr[0]);
 
    // Function call
    binarySearch(arr, size);
 
    return 0;
}

输出：

The array is : 
Geeks, For, GeeksForGeek, 

Searching Result for "Geeks"
String Founded in array

Searching Result for "Best"
String not Found in array

Time Complexity: O(N*log N)
Auxiliary Space: O(1)

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