不包含给定字符串的任何字符的字符串计数

给定一个包含N个字符串的数组arr和一个字符串str ，任务是找出不包含字符串str的任何字符的字符串的数量。

例子：

Input: arr[] = {“abcd”, “hijk”, “xyz”, “ayt”}, str=”apple”
Output: 2
Explanation: “hijk” and “xyz” are the strings that do not contain any character of str

Input: arr[] = {“apple”, “banana”, “pear”}, str=”nil”
Output: 1

方法：按照以下步骤解决此问题：

1. 创建一个集合st并将字符串str 的每个字符存储在该集合中。
2. 创建一个变量ans来存储所有需要的字符串的数量。
3. 现在，开始遍历数组，对于每个字符串，检查它的任何字符是否存在于集合 st 中。如果是，那么这不是必需的字符串。
4. 如果它不包含集合中的任何字符，则将答案增加 1。
5. 循环结束后返回ans ，作为这个问题的答案。

下面是上述方法的实现：

C++

// C++ code for the above approach
 
#include 
using namespace std;
 
// Function to count the number of strings
// that does not contain any character of string str
int allowedStrings(vector& arr, string str)
{
    int ans = 0;
    unordered_set st;
    for (auto x : str) {
        st.insert(x);
    }
 
    for (auto x : arr) {
        bool allowed = 1;
        for (auto y : x) {
 
            // If the character is present in st
            if (st.find(y) != st.end()) {
                allowed = 0;
                break;
            }
        }
 
        // If the string doesn't
        // have any character of st
        if (allowed) {
            ans += 1;
        }
    }
 
    return ans;
}
 
// Driver Code
int main()
{
    vector arr
        = { "abcd", "hijk", "xyz", "ayt" };
    string str = "apple";
    cout << allowedStrings(arr, str);
}

Python3

# Python 3 code for the above approach
 
# Function to count the number of strings
# that does not contain any character of string str
def allowedStrings(arr, st):
    ans = 0
    st1 = set([])
    for x in st:
        st1.add(x)
 
    for x in arr:
        allowed = 1
        for y in x:
 
            # If the character is present in st1
            if (y in st1):
                allowed = 0
                break
 
        # If the string doesn't
        # have any character of st
        if (allowed):
            ans += 1
 
    return ans
 
# Driver Code
if __name__ == "__main__":
 
    arr = ["abcd", "hijk", "xyz", "ayt"]
    st = "apple"
    print(allowedStrings(arr, st))
 
    # This code is contributed by ukasp.

Javascript

// Javascript code for the above approach
 
// Function to count the number of strings
// that does not contain any character of string str
function allowedStrings(arr, str)
{
    let ans = 0;
    let st = new Set();
    for (x of str) {
        st.add(x);
    }
 
    for (x of arr) {
        let allowed = 1;
        for (y of x) {
 
            // If the character is present in st
            if (st.has(y)) {
                allowed = 0;
                break;
            }
        }
 
        // If the string doesn't
        // have any character of st
        if (allowed) {
            ans += 1;
        }
    }
 
    return ans;
}
 
// Driver Code
 
let arr = ["abcd", "hijk", "xyz", "ayt"];
let str = "apple";
document.write(allowedStrings(arr, str));
 
// This code is contributed by gfgking.

输出

2

时间复杂度： O(N*M)，其中 N 是数组的大小，M 是最长字符串的大小。
辅助空间： O(N)