90 lines
2.2 KiB
C++
90 lines
2.2 KiB
C++
#include <string>
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#include <iostream>
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#include <vector>
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#include <span>
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namespace {
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enum Dominoes : char {
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Dot = '.',
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L = 'L',
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R = 'R',
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};
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using Range = std::tuple<size_t, size_t>;
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using Ranges = std::vector<Range>;
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class Solution {
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Ranges findRanges(const std::string& dominoes) {
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Ranges ranges;
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ranges.reserve(dominoes.size() / 2);
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size_t start = -1;
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for (size_t i = 0; i < dominoes.size(); ++i) {
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char d = dominoes[i];
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if (d == Dot && start == -1) {
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start = i;
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} else if (d != Dot && start != -1) {
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ranges.emplace_back(start, i);
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start = -1;
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}
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}
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if (start != -1) {
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ranges.emplace_back(start, dominoes.size());
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}
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return ranges;
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}
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void processRange(const Range& range, std::string& dominoes) {
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bool left_r = false;
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bool right_l = false;
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const auto& [start, end] = range;
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if (start > 0 && dominoes[start - 1] == R)
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left_r = true;
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if (end < (dominoes.size()) && dominoes[end] == L)
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right_l = true;
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if (left_r && right_l) {
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/*
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* 3 4 5 6 7
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* . . . . L
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*/
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auto difference = end - start;
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auto steps = difference / 2;
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for (auto i = 0; i < steps; ++i) {
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dominoes[start + i] = R;
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dominoes[end - 1 - i] = L;
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}
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} else if (left_r) {
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for (auto i = start; i < end; ++i) dominoes[i] = R;
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} else if (right_l) {
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for (auto i = start; i < end; ++i) dominoes[i] = L;
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}
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}
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public:
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std::string pushDominoes(std::string dominoes) {
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auto ranges = findRanges(dominoes);
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for (const auto& range : ranges) {
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auto& [start, end] = range;
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std::cout << "[" << start << ", " << end << "]\n";
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processRange(range, dominoes);
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}
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return dominoes;
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}
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};
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}
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#include <gtest/gtest.h>
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TEST(P838_2, 1) {
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std::string input = ".L.R...LR..L..";
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Solution s;
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auto result = s.pushDominoes(input);
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EXPECT_EQ(result, std::string("LL.RR.LLRRLL.."));
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} |