哈希表,极致占用内存,注意代码规范
#include <bits/stdc++.h>
using namespace std;
int main () {
unordered_map<char, int>rec;
string str;
getline(cin, str);
for (auto it : str) {
rec[it]++;
}
char c;
cin >> c;
int sum = rec[c];
if (c >= 'a' && c <= 'z') {
sum += rec[c - 32];
}
if (c >= 'A' && c <= 'Z'){
sum += rec[c + 32];
}
cout << sum;
return 0;
}