题解 | #字符个数统计#哈希-数组

#include <iostream>
#include <string>

using namespace std;
 
 int caculateNum(string s) {
    int hash[128] = {0};
    int num = 0;
    for (int i = 0; i < s.size(); i++) {
        //确保输入的字符ASCII 码范围在0-127
        if (int(s[i]) >= 0 && int(s[i]) <= 127)
            hash[int(s[i])] = 1;
    }
    for (int i = 0; i < 128; i++) {
        if (hash[i] == 1) {
            num += 1;
        }
    }

    return num;
 }
int main() {
    string n;
    while (cin >> n) { // 注意 while 处理多个 case
        cout << caculateNum(n) << endl;
    }
    return 0;
}
// 64 位输出请用 printf("%lld")