diff --git a/3 b/3
new file mode 100644
index 0000000..153f72b
--- /dev/null
+++ b/3
@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <stdbool.h>
+#define SIZE 9
+void printMatrix(char matrix[SIZE][SIZE]) {
+for (int i = 0; i < SIZE; i++) {
+for (int j = 0; j < SIZE; j++) {
+printf("%c ", matrix[i][j]);
+}
+printf("\n");
+}
+}
+bool isValidSudoku(char matrix[SIZE][SIZE]) {
+bool rowCheck[SIZE][SIZE] = {false};
+bool colCheck[SIZE][SIZE] = {false};
+bool blockCheck[SIZE][SIZE] = {false};
+for (int i = 0; i < SIZE; i++) {
+for (int j = 0; j < SIZE; j++) {
+char c = matrix[i][j];
+if (c == '.') continue;
+int num = c - '1';
+if (rowCheck[i][num]) {
+printf("False: Invalid initial Sudoku matrix!\n");
+printf("The number %d in the row %d has been used!\n", num + 1, i + 1);
+return false;
+}
+rowCheck[i][num] = true;
+if (colCheck[j][num]) {
+printf("False: Invalid initial Sudoku matrix!\n");
+printf("The number %d in the col %d has been used!\n", num + 1, j + 1);
+return false;
+}
+colCheck[j][num] = true;
+int blockIndex = (i / 3) * 3 + (j / 3);
+if (blockCheck[blockIndex][num]) {
+printf("False: Invalid initial Sudoku matrix!\n");
+printf("The number %d in the block %d has been used!\n", num + 1, blockIndex + 1);
+return false;
+}
+blockCheck[blockIndex][num] = true;
+}
+}
+printf("True: Valid initial Sudoku matrix!\n");
+return true;
+}
+int main() {
+char matrix[SIZE][SIZE] = {
+{'5', '3', '.', '.', '7', '.', '.', '.', '.'},
+{'6', '.', '.', '1', '9', '5', '.', '.', '.'},
+{'.', '9', '8', '.', '.', '.', '.', '6', '.'},
+{'8', '.', '.', '.', '6', '.', '.', '.', '3'},
+{'4', '.', '.', '8', '.', '3', '.', '.', '1'},
+{'7', '.', '.', '.', '2', '.', '.', '.', '6'},
+{'.', '6', '.', '.', '.', '.', '2', '8', '.'},
+{'.', '.', '.', '4', '1', '9', '.', '.', '5'},
+{'.', '.', '.', '.', '8', '.', '.', '7', '9'}
+};
+printf("The original Sudoku matrix:\n");
+printMatrix(matrix);
+isValidSudoku(matrix);
+return 0;
+}
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