ignore a.out

.gitignore

@@ -9,3 +9,4 @@
 
 sudoku
 test
+a.out

force.c

@@ -0,0 +1,216 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#define UNDEFINED -1
+
+#define VALUE_TYPE_UNDEFINED UNDEFINED
+#define VALUE_TYPE_STATIC 0
+#define VALUE_TYPE_GUESS 1
+
+#define COLOR_BLACK 0
+#define COLOR_RED 1
+#define COLOR_GREEN 2
+#define COLOR_YELLOW 3
+#define COLOR_BLUE 4
+#define COLOR_MAGENTA 5
+#define COLOR_CYAN 6
+#define COLOR_WHITE 7
+
+#define COLOR_FG 30
+#define COLOR_BG 40
+
+struct Value {
+	int valueType;
+	int value;
+};
+
+/*
+int sudoku[9][9] = {
+	{5, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 1, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 4, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 1, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 2},
+	{7, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 3, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 5, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 7, 3, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 6, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, 2, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 6, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 4, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, 9, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 8, 3, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, 8, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 4, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 2},
+	{4, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 6, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 7, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 1, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, 9}
+};
+*/
+struct Value sudoku[9][9] = {
+	{{VALUE_TYPE_STATIC, 5}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 1}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 4}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 1}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 2}},
+	{{VALUE_TYPE_STATIC, 7}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 3}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 5}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 7}, {VALUE_TYPE_STATIC, 3}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 6}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 2}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 6}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 4}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 9}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 8}, {VALUE_TYPE_STATIC, 3}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 8}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 4}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 2}},
+	{{VALUE_TYPE_STATIC, 4}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 6}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 7}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}},
+	{{VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 1}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_UNDEFINED, UNDEFINED}, {VALUE_TYPE_STATIC, 9}}
+};
+
+int calculateRow(int q, int f) { 
+	return (q / 3) * 3 + (f / 3);
+}
+
+int calculateCol(int q, int f) {
+	return (q % 3) * 3 + (f % 3);
+}
+
+int calculateQuadrat(int row, int col) {
+	return (row / 3) * 3 + col / 3;
+}
+
+int calculateField(int row, int col) {
+	return (row % 3) * 3 + col % 3;
+}
+
+// checks if this value is present anywhere in the row
+bool isInRow(int row, int val) {
+	for (int col = 0; col < 9; col++) {
+		int q = calculateQuadrat(row, col);
+		int f = calculateField(row, col);
+
+		if (sudoku[q][f].valueType != VALUE_TYPE_UNDEFINED && sudoku[q][f].value == val) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+// checks if this value is present anywhere in the col
+bool isInCol(int col, int val) {
+	for (int row = 0; row < 9; row++) {
+		int q = calculateQuadrat(row, col);
+		int f = calculateField(row, col);
+
+		if (sudoku[q][f].valueType != VALUE_TYPE_UNDEFINED && sudoku[q][f].value == val) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+// checks if this value is present anywhere in the quadrat
+bool isInQuadrat(int q, int val) {
+	for (int f = 0; f < 9; f++) {
+		if (sudoku[q][f].valueType != VALUE_TYPE_UNDEFINED && sudoku[q][f].value == val) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+// check if val is possible value
+// i.e. not in row, not in col, not in q
+bool check(int q, int f, int val) {
+	int row = calculateRow(q, f);
+	int col = calculateCol(q, f);
+
+	return !isInRow(row, val)
+		&& !isInCol(col, val)
+		&& !isInQuadrat(q, val);
+}
+
+void printDumpSudoku() {
+	printf("\033[H\033[J");
+	for (int row = 0; row < 9; row++) {
+		if (row % 3 == 0) {
+			printf("+-------+-------+-------+\n");
+		}
+		for (int col = 0; col < 9; col++) {
+			if (col % 3 == 0) {
+				if (col != 0) {
+					printf(" ");
+				}
+				printf("|");
+			}
+
+			int q = calculateQuadrat(row, col);
+			int f = calculateField(row, col);
+			if (sudoku[q][f].valueType != VALUE_TYPE_UNDEFINED) {
+				int color;
+				if (sudoku[q][f].valueType == VALUE_TYPE_STATIC) {
+					color = COLOR_FG + COLOR_BLUE;
+				} else if (sudoku[q][f].valueType == VALUE_TYPE_GUESS) {
+					color = COLOR_FG + COLOR_GREEN;
+				}
+				printf(" \033[%dm%d\033[0m", color, sudoku[q][f].value);
+			} else {
+				printf(" -");
+			}
+		}
+		printf(" |\n");
+	}
+	printf("+-------+-------+-------+\n");
+}
+
+
+int main() {
+	long iterations = 0;
+	long guesses = 0;
+	for (int q = 0; q < 9; q++) {
+		for (int f = 0; f < 9; f++) {
+			if (sudoku[q][f].valueType == VALUE_TYPE_STATIC) {
+				continue;
+			}
+
+			iterations++;
+
+			// initialize start value
+			// might not be 1 if this field was already guessed but we had to go back
+			// because the guessed value failed later
+			int startVal;
+			if (sudoku[q][f].value > UNDEFINED) {
+				startVal = sudoku[q][f].value + 1;
+			} else {
+				startVal = 1;
+			}
+
+			// loop through values, if one possible value is found (value is neither in row nor in column)
+			// continue to next field
+			for (int val = startVal; val <= 9 && sudoku[q][f].valueType == VALUE_TYPE_UNDEFINED; val++) {
+				if (check(q, f, val)) {
+					sudoku[q][f].valueType = VALUE_TYPE_GUESS;
+					sudoku[q][f].value = val;
+				}
+			}
+
+			// check if a possible value was found
+			// if not, go backwards to last guessed value
+			if (sudoku[q][f].valueType == VALUE_TYPE_UNDEFINED) {
+				// reset value for next time we get back at
+				// this position for a guess
+				sudoku[q][f].value = UNDEFINED;
+				while (sudoku[q][f].valueType != VALUE_TYPE_GUESS) {
+					f--;
+					if (f < 0) {
+						q--;
+						if (q < 0) {
+							fprintf(stderr, "Error: going backwards made q < 0\n");
+							return 1;
+						}
+						f = 8;
+					}
+				}
+				sudoku[q][f].valueType = VALUE_TYPE_UNDEFINED;
+				f--; // next iteration will increment f at beginning (for loop)
+			} else {
+				// good, possible value found
+				//printDumpSudoku();
+				//usleep(10 * 1000);
+				guesses++;
+			}
+		}
+	}
+
+	printDumpSudoku();
+	printf("Iterations: %ld\n", iterations);
+	printf("Guesses: %ld\n", guesses);
+
+	return 0;
+}

sudoku.c

@@ -27,6 +27,7 @@ int sudoku[9][9] = {
 */
 
 // https://www.free-sudoku.com/sudoku.php?dchoix=evil
+/*
 int sudoku[9][9] = {
     {VALUE_UNDEFINED,1,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED},
     {3,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,8,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED},
@@ -38,6 +39,19 @@ int sudoku[9][9] = {
     {1,VALUE_UNDEFINED,VALUE_UNDEFINED,6,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED},
     {5,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,8,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED,VALUE_UNDEFINED}
 };
+*/
+
+int sudoku[9][9] = {
+    {5, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 1, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, VALUE_UNDEFINED, 4, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 1, VALUE_UNDEFINED, 2},
+    {7, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 3, VALUE_UNDEFINED, VALUE_UNDEFINED, 5, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, VALUE_UNDEFINED, 7, 3, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 6, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, 2, VALUE_UNDEFINED, VALUE_UNDEFINED, 6, VALUE_UNDEFINED, VALUE_UNDEFINED, 4, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, 9, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 8, 3, VALUE_UNDEFINED, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, 8, VALUE_UNDEFINED, VALUE_UNDEFINED, 4, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 2},
+    {4, VALUE_UNDEFINED, 6, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 7, VALUE_UNDEFINED, VALUE_UNDEFINED},
+    {VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 1, VALUE_UNDEFINED, VALUE_UNDEFINED, VALUE_UNDEFINED, 9}
+};
 
 void readQ(int num) {
     printf("Enter every number of Q%d from left top to right bottom. Use `0` if on no initial value:\n", num + 1);
@@ -225,9 +239,9 @@ bool isInQuadrat(int q, int val) {
     return false;
 }
 
-void setValue(int q, int f, int val) {
+void setValue(int q, int f, int val, char* rule) {
     sudoku[q][f] = val;
-    printf("=> setting %d in Q %d; F %d\n", val, q, f);
+    printf("=> setting %d in Q %d; F %d (%s)\n", val, q, f, rule);
     //printDumpSudoku();
 }
 
@@ -276,12 +290,14 @@ int main() {
             };
 
             for (int val = 1; val <= 9; val++) {
+	        // val is already set in quadrat, go ahead
                 if (isInQuadrat(q, val)) {
                     continue;
                 }
 
                 int possibleField = FIELD_UNDEFINED;
                 for (int f = 0; f < 9; f++) {
+		    // calculate row and col of current field in quadrant
                     int row = calculateRow(q, f);
                     int col = calculateCol(q, f);
 
@@ -310,12 +326,12 @@ int main() {
 
                 // found possible field? set val
                 if (possibleField > FIELD_UNDEFINED) {
-                    setValue(q, possibleField, val);
+                    setValue(q, possibleField, val, "standard col/row check");
                     somethingChanged = true;
                 }
             }
 
-            // check if only one field is left undefined -> hast to be the one special value
+            // check if only one field is left undefined -> has to be the one special value
             for (int f = 0; f < 9; f++) {
                 // keep in mind that sudoku array might have changed since evaluation
                 // -> ignore already set values
@@ -324,7 +340,7 @@ int main() {
                 }
 
                 if (possbileVal[f] > VALUE_UNDEFINED) {
-                    setValue(q, f, possbileVal[f]);
+                    setValue(q, f, possbileVal[f], "every other value is not possible here");
                     somethingChanged = true;
                 } else {
                     // set to undefined, multiple or any other meta information