79 lines
1.5 KiB
C++
79 lines
1.5 KiB
C++
#include <cassert>
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#include <functional>
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#include <iostream>
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#include <string>
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auto illegal_char(char c) -> bool { return c == 'i' || c == 'l' || c == 'o'; }
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void pre_advance_password(std::string& s)
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{
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std::string::size_type pos = 0;
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while (pos < s.length() && !illegal_char(s[pos])) {
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++pos;
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}
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if (pos == s.length()) {
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return;
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}
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++s[pos++];
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while (pos < s.length()) {
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s[pos++] = 'a';
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}
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}
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void advance_password(std::string& s)
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{
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auto pos = s.length() - 1;
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while (true) {
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if (s[pos] == 'z') {
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assert(pos != 0);
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s[pos] = 'a';
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pos -= 1;
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}
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else {
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++s[pos];
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if (illegal_char(s[pos])) {
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++s[pos];
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}
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return;
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}
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}
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}
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auto valid_password(std::string const& s) -> bool
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{
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unsigned double_count = 0;
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bool run = false;
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char last2 = '\0';
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char last = '\0';
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for (auto c : s) {
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if (c == last && last2 != c) {
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++double_count;
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}
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else if (c == last + 1 && c == last2 + 2) {
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run = true;
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}
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last2 = last;
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last = c;
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}
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return double_count >= 2 && run;
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}
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auto next_password(std::string const& s) -> std::string
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{
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std::string result = s;
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pre_advance_password(result);
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do {
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advance_password(result);
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} while (!valid_password(result));
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return result;
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}
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auto main() -> int
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{
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for (std::string line; std::getline(std::cin, line);) {
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std::string next = next_password(line);
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std::cout << "Current password: " << line << "; Next password: " << next << "\n";
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}
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return 0;
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} |