解法一

✅ 完整代碼

評分結果(參考) ： AC (2ms, 352KB)

#include <bits/stdc++.h>
using namespace std;

int letter2num(char c){
    switch(c){
        case 'A': return 1+0*9;        case 'N': return 2+2*9;
        case 'B': return 1+1*9;        case 'O': return 3+5*9;
        case 'C': return 1+2*9;        case 'P': return 2+3*9;
        case 'D': return 1+3*9;        case 'Q': return 2+4*9;
        case 'E': return 1+4*9;        case 'R': return 2+5*9;
        case 'F': return 1+5*9;        case 'S': return 2+6*9;
        case 'G': return 1+6*9;        case 'T': return 2+7*9;
        case 'H': return 1+7*9;        case 'U': return 2+8*9;
        case 'I': return 3+4*9;        case 'V': return 2+9*9;
        case 'J': return 1+8*9;        case 'W': return 3+2*9;
        case 'K': return 1+9*9;        case 'X': return 3+0*9;
        case 'L': return 2+0*9;        case 'Y': return 3+1*9;
        case 'M': return 2+1*9;        case 'Z': return 3+3*9;
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    string s;
    cin >> s;

    int sum = 0;
    for(int i=0; i<9; i++){
        sum += (s[i]-'0') * (8-i);
    }
    sum += (s[8]-'0');

    for(int i=0; i<26; i++){
        if((sum + letter2num('A'+i))%10 == 0){
            cout << (char)('A' + i);
        }
    }
    
    return 0;
}