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Commit 53f8a6e

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Merge pull request #7 from RasimSadikoglu/master
Algorithm - 2 -> C++ DFS Solution
2 parents e3acf29 + 8ce9e9b commit 53f8a6e

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2 files changed

+182
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‎algorithm-2/C++/README.md‎

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Katkıda bulunmak istiyorsanız, lütfen aşağıdaki adımları takip edin:
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5-
İlgili algoritma için çözümünüzü repo içerisinde kaç tane çözüm varsa ona göre isimlendirin. Eğer 2 adet çözüm varsa kendi çözümünüzü "solution-3.cs" şeklinde kaydedebilirsiniz.
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İlgili algoritma için çözümünüzü repo içerisinde kaç tane çözüm varsa ona göre isimlendirin. Eğer 2 adet çözüm varsa kendi çözümünüzü "solution-3.cpp" şeklinde kaydedebilirsiniz.
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Bu numaralandırma şekliyle çözümleri daha derli toplu tutmayı hedefliyoruz. Farklı isimlendirmeler ile gönderilen PR 'lar otomatik olarak reddedilecektir.

‎algorithm-2/C++/solution-1.cpp‎

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// Usage: g++ -Ofast solution-1.cpp -o solution && .\solution
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#include <array>
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#include <bitset>
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#include <iostream>
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#include <memory>
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#include <numeric>
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#include <vector>
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#include <stack>
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enum BoardStatus {
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NOT_FINISHED,
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FINISHED,
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ILLEGAL
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};
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class Board {
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private:
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std::array<uint8_t, 81> cells;
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public:
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Board(std::array<uint8_t, 81> cells): cells{cells} {}
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void set_cell(uint8_t cell, uint8_t val) {
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cells[cell] = val;
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}
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bool is_cell_empty(uint8_t cell) {
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return !cells[cell];
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}
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BoardStatus check_board() const {
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auto status = FINISHED;
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std::bitset<81>
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lateral_set,
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vertical_set,
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sub_set;
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for (uint8_t index = 0; index < 81; index++) {
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uint8_t
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x = index % 9,
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y = index / 9,
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val = cells[index] - 1; // 0 is empty, 0 - 1 = 255 (unsigned)
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if (val > 9) {
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status = NOT_FINISHED;
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continue;
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}
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uint8_t
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lateral_set_index = y * 9 + val,
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vertical_set_index = val * 9 + x,
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sub_set_index = ((y / 3 * 3) + val / 3) * 9 + ((x / 3 * 3) + val % 3);
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if (
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lateral_set.test(lateral_set_index) ||
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vertical_set.test(vertical_set_index) ||
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sub_set.test(sub_set_index)
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) return ILLEGAL;
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lateral_set.set(lateral_set_index);
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vertical_set.set(vertical_set_index);
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sub_set.set(sub_set_index);
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}
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return status;
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}
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void print() const {
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for (uint8_t index = 0; index < 81; index++) {
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int val = static_cast<int>(cells[index]);
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std::cout << " " << (val ? val : ' ') << " ";
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if (index % 9 == 8) std::cout << "\n";
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}
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}
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};
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class BoardStack {
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private:
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std::shared_ptr<Board> board;
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std::stack<std::pair<uint8_t, uint8_t>> move_stack; // std::pair<first: cell, second: val>
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public:
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BoardStack(std::shared_ptr<Board> board): board{board} {}
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void make_move(uint8_t cell, uint8_t val) {
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board->set_cell(cell, val);
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move_stack.push({cell, val});
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}
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std::pair<uint8_t, uint8_t> undo_move() {
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auto prev_move = move_stack.top();
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board->set_cell(prev_move.first, 0);
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move_stack.pop();
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return prev_move;
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}
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bool is_empty() const {
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return move_stack.empty();
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}
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};
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class SudokuSolver {
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private:
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std::shared_ptr<Board> board;
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BoardStack board_stack;
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std::vector<uint8_t> empty_cells;
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public:
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SudokuSolver(std::shared_ptr<Board> board):
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board{board},
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board_stack{BoardStack(board)} {
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init_empty_cells();
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}
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BoardStatus solve() {
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BoardStatus status;
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uint8_t current_empty_cell = 0, last_value = 0;
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while ((status = board->check_board()) != FINISHED) {
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if (status == ILLEGAL || last_value == 9) {
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if (board_stack.is_empty()) break;
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auto last_move = board_stack.undo_move();
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last_value = last_move.second;
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current_empty_cell--;
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continue;
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}
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board_stack.make_move(empty_cells[current_empty_cell++], last_value + 1);
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last_value = 0;
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}
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return status;
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}
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private:
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void init_empty_cells() {
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for (uint8_t index = 0; index < 81; index++) {
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if (board->is_cell_empty(index)) empty_cells.push_back(index);
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}
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}
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};
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std::array<uint8_t, 81> parse() {
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std::array<uint8_t, 81> cells;
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for (uint8_t index = 0; index < 81;) {
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char ch;
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std::cin >> ch;
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if (!isdigit(ch)) continue;
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cells[index++] = ch - '0';
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}
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return cells;
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}
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void solve() {
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auto cells = parse();
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auto board = std::make_shared<Board>(Board(cells));
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if (board->check_board() == ILLEGAL) {
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std::cout << "Initial board is in an illagel state!\n";
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return;
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}
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SudokuSolver(board).solve();
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if (board->check_board() == NOT_FINISHED) {
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std::cout << "The board is not solveable!\n";
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return;
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}
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board->print();
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}
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int main(void) {
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solve();
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}

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