백준 14726번: 신용카드 판별

https://www.acmicpc.net/problem/14726

1. 문제

2. 알고리즘

키워드 - 구현, 수학

3. 코드

#include <iostream>
#include <sstream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <list>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <stack>
#include <math.h>
#include <memory.h>
using namespace std;
 
#define MAX_SIZE 100
#define INF 0x7fffffff
#define CENDL "\n"
#define ll long long
 
#define c_reverse(s) reverse(s.begin(), s.end())
#define c_sort(s) sort(s.begin(), s.end())
#define print_vector(v) for(int i=0; i<v.size(); i++) cout << v[i];
 
int devide(int n) {
    int ret = n % 10;
    n /= 10;
    return ret + n;
}
 
bool solve(string s) {
    int sol = 0;
 
    reverse(s.begin(), s.end());
    const int size = s.size();
    
    for (int i=0; i<size; i++) {
        char ch = s[i] - '0';
 
        if ((i+1) % 2 == 0) {
            int cand = ch * 2;
 
            while(cand > 9) {
                cand = devide(cand);
            }
 
            sol += cand;
        } else {
            sol += ch;
        }
    }
 
    if (sol % 10 == 0) {
        return true;
    }
    return false;
}
 
int main() {
 
    cin.tie(0);
    std::ios::sync_with_stdio(false);
    
    int n; cin >> n;
    
    while(n--) {
        string s; cin >> s;
 
        bool isOk = solve(s);
 
        if (isOk) {
            cout << "T" << CENDL;
        } else {
            cout << "F" << CENDL; 
        }
    }
 
    return 0; 
}