#include <cctype> #include <iostream> #include <unordered_set> #include <string> using namespace std; int countC(string s, char c){ int res = 0; unordered_multiset<char> set; for(char i : s){ set.insert(tolower(i)); } res = set.count(tolower(c)); return res; } int main() { string s; char c; getline(cin, s); cin >> c; cout << countC(s, c) << endl; return 0; } // 64 位输出请用 printf("%lld")
unordered_multiset<char> 无序多元(值可重复),非键值对
set.insert();
set.count();