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| 1 | #include <iostream> | |
| 2 | #include <Windows.h> | |
| 3 | #include <conio.h> | |
| 4 | ||
| 5 | using namespace std; | |
| 6 | ||
| 7 | char sudoku[9][9]; | |
| 8 | ||
| 9 | void printSudoku(bool); | |
| 10 | void recursiveScan(); | |
| 11 | void method1(bool &); | |
| 12 | void method2(bool &); | |
| 13 | bool checkBox(int, int, char); | |
| 14 | ||
| 15 | int main() | |
| 16 | {
| |
| 17 | // initialize sudoku[][] | |
| 18 | for (int i = 0; i < 9; i++) | |
| 19 | {
| |
| 20 | for (int j = 0; j < 9; j++) | |
| 21 | {
| |
| 22 | sudoku[i][j] = ' '; | |
| 23 | } | |
| 24 | } | |
| 25 | // print empty grid | |
| 26 | printSudoku(false); | |
| 27 | // input sudoku | |
| 28 | printSudoku(true); | |
| 29 | system("pause");
| |
| 30 | system("CLS");
| |
| 31 | // solve sudoku | |
| 32 | recursiveScan(); | |
| 33 | system("pause");
| |
| 34 | return 0; | |
| 35 | } | |
| 36 | ||
| 37 | void printSudoku(bool input) | |
| 38 | {
| |
| 39 | // reset cursor position | |
| 40 | COORD cursor = { 0, 0 };
| |
| 41 | SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), cursor); | |
| 42 | char key; | |
| 43 | for (int i = 0; i < 9; i++) | |
| 44 | {
| |
| 45 | for (int j = 0; j < 9; j++) | |
| 46 | {
| |
| 47 | switch (j) | |
| 48 | {
| |
| 49 | case 0: | |
| 50 | {
| |
| 51 | // print grid rows | |
| 52 | switch (i) | |
| 53 | {
| |
| 54 | case 1: | |
| 55 | case 2: | |
| 56 | case 4: | |
| 57 | case 5: | |
| 58 | case 7: | |
| 59 | case 8: | |
| 60 | {
| |
| 61 | cout << char(196) | |
| 62 | << char(197) | |
| 63 | << char(196) | |
| 64 | << char(197) | |
| 65 | << char(196) | |
| 66 | << char(186) | |
| 67 | << char(196) | |
| 68 | << char(197) | |
| 69 | << char(196) | |
| 70 | << char(197) | |
| 71 | << char(196) | |
| 72 | << char(186) | |
| 73 | << char(196) | |
| 74 | << char(197) | |
| 75 | << char(196) | |
| 76 | << char(197) | |
| 77 | << char(196) | |
| 78 | << '\n'; | |
| 79 | break; | |
| 80 | } | |
| 81 | case 3: | |
| 82 | case 6: | |
| 83 | {
| |
| 84 | cout << char(205) | |
| 85 | << char(205) | |
| 86 | << char(205) | |
| 87 | << char(205) | |
| 88 | << char(205) | |
| 89 | << char(206) | |
| 90 | << char(205) | |
| 91 | << char(205) | |
| 92 | << char(205) | |
| 93 | << char(205) | |
| 94 | << char(205) | |
| 95 | << char(206) | |
| 96 | << char(205) | |
| 97 | << char(205) | |
| 98 | << char(205) | |
| 99 | << char(205) | |
| 100 | << char(205) | |
| 101 | << '\n'; | |
| 102 | break; | |
| 103 | } | |
| 104 | default: | |
| 105 | {
| |
| 106 | break; | |
| 107 | } | |
| 108 | } | |
| 109 | break; | |
| 110 | } | |
| 111 | // print grid columns | |
| 112 | case 1: | |
| 113 | case 2: | |
| 114 | case 4: | |
| 115 | case 5: | |
| 116 | case 7: | |
| 117 | case 8: | |
| 118 | {
| |
| 119 | cout << char(179); | |
| 120 | break; | |
| 121 | } | |
| 122 | case 3: | |
| 123 | case 6: | |
| 124 | {
| |
| 125 | cout << char(186); | |
| 126 | break; | |
| 127 | } | |
| 128 | default: | |
| 129 | break; | |
| 130 | } | |
| 131 | // get initial sudoku from user | |
| 132 | if (input) | |
| 133 | {
| |
| 134 | do | |
| 135 | {
| |
| 136 | key = _getch(); | |
| 137 | } while (!strchr("123456789 ", key));
| |
| 138 | sudoku[i][j] = key; | |
| 139 | } | |
| 140 | cout << sudoku[i][j]; | |
| 141 | } | |
| 142 | cout << '\n'; | |
| 143 | } | |
| 144 | } | |
| 145 | ||
| 146 | // perform both methods while either method is still successful | |
| 147 | void recursiveScan() | |
| 148 | {
| |
| 149 | bool meth1, meth2; | |
| 150 | do | |
| 151 | {
| |
| 152 | printSudoku(false); | |
| 153 | method1(meth1); | |
| 154 | method2(meth2); | |
| 155 | Sleep(500); | |
| 156 | } while (meth1 || meth2); | |
| 157 | } | |
| 158 | ||
| 159 | // test if each box can only be a specific number | |
| 160 | void method1(bool &meth1) | |
| 161 | {
| |
| 162 | meth1 = false; | |
| 163 | bool boxes[9]; | |
| 164 | for (int i = 0; i < 9; i++) | |
| 165 | {
| |
| 166 | for (int j = 0; j < 9; j++) | |
| 167 | {
| |
| 168 | // if current box is already solved, abort | |
| 169 | if (sudoku[i][j] != ' ') | |
| 170 | {
| |
| 171 | continue; | |
| 172 | } | |
| 173 | // initialize boxes[] | |
| 174 | for (int k = 0; k < 9; k++) | |
| 175 | {
| |
| 176 | boxes[k] = true; | |
| 177 | } | |
| 178 | // keep track of which numbers this box cannot be | |
| 179 | for (int ii = 0; ii < 9; ii++) | |
| 180 | {
| |
| 181 | if (sudoku[ii][j] != ' ') | |
| 182 | {
| |
| 183 | boxes[(sudoku[ii][j] - '0') - 1] = false; | |
| 184 | } | |
| 185 | } | |
| 186 | for (int jj = 0; jj < 9; jj++) | |
| 187 | {
| |
| 188 | if (sudoku[i][jj] != ' ') | |
| 189 | {
| |
| 190 | boxes[(sudoku[i][jj] - '0') - 1] = false; | |
| 191 | } | |
| 192 | } | |
| 193 | for (int ii = i - (i % 3); ii < i - (i % 3) + 3; ii++) | |
| 194 | {
| |
| 195 | for (int jj = j - (j % 3); jj < j - (j % 3) + 3; jj++) | |
| 196 | {
| |
| 197 | if (sudoku[ii][jj] != ' ') | |
| 198 | {
| |
| 199 | boxes[(sudoku[ii][jj] - '0') - 1] = false; | |
| 200 | } | |
| 201 | } | |
| 202 | } | |
| 203 | // count how many numbers this box can be | |
| 204 | int options = 0; | |
| 205 | char answer; | |
| 206 | for (int k = 0; k < 9; k++) | |
| 207 | {
| |
| 208 | if (boxes[k] == true) | |
| 209 | {
| |
| 210 | options++; | |
| 211 | if (options > 1) | |
| 212 | {
| |
| 213 | break; | |
| 214 | } | |
| 215 | answer = k + 1 + '0'; | |
| 216 | } | |
| 217 | } | |
| 218 | // if this box can only be one number, success | |
| 219 | if (options == 1) | |
| 220 | {
| |
| 221 | sudoku[i][j] = answer; | |
| 222 | meth1 = true; | |
| 223 | } | |
| 224 | } | |
| 225 | } | |
| 226 | } | |
| 227 | ||
| 228 | // test if each row/column/3x3 box has only one space left for a specific number | |
| 229 | void method2(bool &meth2) | |
| 230 | {
| |
| 231 | meth2 = false; | |
| 232 | int options; | |
| 233 | int answeri, answerj; | |
| 234 | for (char n = '1'; n <= '9'; n++) | |
| 235 | {
| |
| 236 | for (int i = 0; i < 9; i++) | |
| 237 | {
| |
| 238 | // keep track of how many boxes in this row can be n | |
| 239 | options = 0; | |
| 240 | for (int j = 0; j < 9; j++) | |
| 241 | {
| |
| 242 | if (checkBox(i, j, n)) | |
| 243 | {
| |
| 244 | options++; | |
| 245 | if (options > 1) | |
| 246 | {
| |
| 247 | break; | |
| 248 | } | |
| 249 | answerj = j; | |
| 250 | } | |
| 251 | } | |
| 252 | // if only one box in this row can be n, success | |
| 253 | if (options == 1) | |
| 254 | {
| |
| 255 | sudoku[i][answerj] = n; | |
| 256 | meth2 = true; | |
| 257 | } | |
| 258 | } | |
| 259 | for (int j = 0; j < 9; j++) | |
| 260 | {
| |
| 261 | // keep track of how many boxes in this column can be n | |
| 262 | options = 0; | |
| 263 | for (int i = 0; i < 9; i++) | |
| 264 | {
| |
| 265 | if (checkBox(i, j, n)) | |
| 266 | {
| |
| 267 | options++; | |
| 268 | if (options > 1) | |
| 269 | {
| |
| 270 | break; | |
| 271 | } | |
| 272 | answeri = i; | |
| 273 | } | |
| 274 | } | |
| 275 | // if only one box in this column can be n, success | |
| 276 | if (options == 1) | |
| 277 | {
| |
| 278 | sudoku[answeri][j] = n; | |
| 279 | meth2 = true; | |
| 280 | } | |
| 281 | } | |
| 282 | for (int i = 0; i <= 6; i += 3) | |
| 283 | {
| |
| 284 | for (int j = 0; j <= 6; j += 3) | |
| 285 | {
| |
| 286 | // keep track of how many boxes in this 3x3 box can be n | |
| 287 | options = 0; | |
| 288 | for (int ii = i; ii < i + 3; ii++) | |
| 289 | {
| |
| 290 | for (int jj = j; jj < j + 3; jj++) | |
| 291 | {
| |
| 292 | if (checkBox(ii, jj, n)) | |
| 293 | {
| |
| 294 | options++; | |
| 295 | if (options > 1) | |
| 296 | {
| |
| 297 | break; | |
| 298 | } | |
| 299 | answeri = ii; | |
| 300 | answerj = jj; | |
| 301 | } | |
| 302 | } | |
| 303 | } | |
| 304 | // if only one box in this 3x3 box can be n, success | |
| 305 | if (options == 1) | |
| 306 | {
| |
| 307 | sudoku[answeri][answerj] = n; | |
| 308 | meth2 = true; | |
| 309 | } | |
| 310 | } | |
| 311 | } | |
| 312 | } | |
| 313 | } | |
| 314 | ||
| 315 | // test if sudoku[i][j] may be n | |
| 316 | bool checkBox(int i, int j, char n) | |
| 317 | {
| |
| 318 | if (sudoku[i][j] != ' ') | |
| 319 | return false; | |
| 320 | // search this column for n | |
| 321 | for (int ii = 0; ii < 9; ii++) | |
| 322 | {
| |
| 323 | if (sudoku[ii][j] == n) | |
| 324 | {
| |
| 325 | return false; | |
| 326 | } | |
| 327 | } | |
| 328 | // search this row for n | |
| 329 | for (int jj = 0; jj < 9; jj++) | |
| 330 | {
| |
| 331 | if (sudoku[i][jj] == n) | |
| 332 | {
| |
| 333 | return false; | |
| 334 | } | |
| 335 | } | |
| 336 | // search this 3x3 box for n | |
| 337 | for (int ii = i - (i % 3); ii < i - (i % 3) + 3; ii++) | |
| 338 | {
| |
| 339 | for (int jj = j - (j % 3); jj < j - (j % 3) + 3; jj++) | |
| 340 | {
| |
| 341 | if (sudoku[ii][jj] == n) | |
| 342 | {
| |
| 343 | return false; | |
| 344 | } | |
| 345 | } | |
| 346 | } | |
| 347 | // n was not found | |
| 348 | return true; | |
| 349 | } |
