45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
#include <algorithm>
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#include <iostream>
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#include <string>
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// Check if a string is nice:
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// Nice strings have:
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// repeated double letters - but not overlapping
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// repeated letters separated by one other.
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auto is_nice(std::string const& s) noexcept -> bool
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{
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bool repeated_pair = false;
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bool repeated_sep = false;
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std::cout << s;
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for (std::string::size_type i = 0; i < s.length() - 2; ++i) {
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// Find whether the two characters starting at `i` are repeated in the rest of
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// the string. We don't have to look backwards as we will already have
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// scanned it.
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if (s.substr(i + 2).find(s.substr(i, 2)) != std::string::npos) {
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repeated_pair = true;
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std::cout << " repeated(" << s.substr(i, 2) << ")";
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}
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if (s[i] == s[i + 2]) {
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repeated_sep = true;
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std::cout << " pair(" << s.substr(i, 3) << ")";
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}
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}
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if (repeated_pair && repeated_sep) {
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std::cout << " match";
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}
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std::cout << "\n";
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return repeated_pair && repeated_sep;
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}
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auto main() -> int
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{
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unsigned nice_strings{0};
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for (std::string line; std::getline(std::cin, line);) {
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nice_strings += is_nice(line) ? 1 : 0;
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}
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std::cout << nice_strings << '\n';
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return 0;
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} |