Softeer - 플레이페어 암호

https://softeer.ai/practice/result.do?eventIdx=1&psProblemId=804&submissionSn=SW_PRBL_SBMS_43166#hold 

https://softeer.ai/practice/result.do?eventIdx=1&psProblemId=804&submissionSn=SW_PRBL_SBMS_43166#hold

#include <iostream>
#include <string>
#include <map>


using namespace std;


char key_tbl[5][5];
string new_msg("");
map<char, int> key_map;


void makeKeyTable(string key) {
	bool visit[26] = { 0, };
	visit['J' - 'A'] = true;
	int c = 0;

	for (int i = 0; i < key.size(); ++i) {
		if (visit[key[i] - 'A']) continue;
		visit[key[i] - 'A'] = true;
		key_tbl[c / 5][c % 5] = key[i]; 
		key_map[key[i]] = c++;
	}

	if (c == 25) return;
	
	for (int i = 0; i < 26; ++i) {
		if (visit[i]) continue;
		key_tbl[c / 5][c % 5] = 'A' + i;
		key_map['A' + i] = c++;
	}
}


void makeNewMsg(string msg) {
	new_msg.resize(msg.size() * 2);
	int c = 0;
	for (int i = 0; i < msg.size(); ) {
		char cur = msg[i];
		new_msg[i + c] = cur;

		if (++i == msg.size()) {
			new_msg[i + c++] = 'X';
			break;
		}
		
		int j = i + c;

		char next = msg[i];
		if (cur == next) {
			next = cur != 'X' ? 'X' : 'Q';
			++c;
		}
		else {
			++i;
		}

		new_msg[j] = next;
	}

	new_msg.resize(msg.size() + c);
}


string solve() {
	string answer(new_msg);
	int c = 0;
	for (int i = 0; i < new_msg.size(); ) {
		char val[] = { new_msg[i++], new_msg[i++] };
		if (val[0] < 'A') return answer;

		int rank[] = { key_map[val[0]], key_map[val[1]] };
		int row[] = { rank[0] / 5, rank[1] / 5 };
		int col[] = { rank[0] % 5, rank[1] % 5 };

		if (row[0] == row[1]) {
			answer[c++] = key_tbl[row[0]][(++col[0]) % 5];
			answer[c++] = key_tbl[row[1]][(++col[1]) % 5];
			continue;
		}

		if (col[0] == col[1]) {
			answer[c++] = key_tbl[++row[0] % 5][col[0]];
			answer[c++] = key_tbl[++row[1] % 5][col[1]];
			continue;
		}

		answer[c++] = key_tbl[row[0]][col[1]];
		answer[c++] = key_tbl[row[1]][col[0]];
	}
	return answer;
}


int main() {
	string msg, key;
	cin >> msg >> key;

	makeKeyTable(key);
	makeNewMsg(msg);

	cout << solve() << "\n";
	return 0;
}