diff --git a/task 3.c b/task 3.c
new file mode 100644
index 0000000..e0b443f
--- /dev/null
+++ b/task 3.c	
@@ -0,0 +1,101 @@
+#include <stdio.h>
+#include <stdbool.h>
+#define SIZE 9
+bool isValidSudoku(int matrix[SIZE][SIZE]);
+bool checkRow(int matrix[SIZE][SIZE], int row, int num);
+bool checkCol(int matrix[SIZE][SIZE], int col, int num);
+bool checkBlock(int matrix[SIZE][SIZE], int startRow, int startCol, int num);
+char errorMessage[100];
+int main() {
+    int sudoku[SIZE][SIZE] = {
+        {1, 1, 6, 9, 8, 5, 0, 0, 0},
+        {0, 0, 0, 1, 0, 2, 0, 0, 0},
+        {2, 3, 0, 0, 5, 7, 6, 0, 4},
+        {8, 0, 0, 0, 0, 0, 0, 0, 9},
+        {0, 0, 0, 0, 0, 0, 0, 0, 0},
+        {0, 0, 0, 0, 0, 0, 0, 0, 0},
+        {0, 0, 0, 0, 0, 0, 0, 0, 0},
+        {0, 0, 0, 0, 0, 0, 0, 0, 0},
+        {0, 0, 0, 0, 0, 0, 0, 0, 0}
+    };
+    printf("The original Sudoku matrix:\n");
+    int i,j;
+    for (i = 0; i < SIZE; i++) {
+        for (j = 0; j < SIZE; j++) {
+            printf("%d ", sudoku[i][j]);
+        }
+        printf("\n");
+    }
+    if (!isValidSudoku(sudoku)) {
+        printf("False: Invalid initial Sudoku matrix!\n");
+        if (errorMessage[0] != '\0') { // 检查错误信息是否为空
+            printf("%s\n", errorMessage);
+        }
+    } else {
+        printf("True: Valid initial Sudoku matrix!\n");
+    }
+    return 0;
+}bool isValidSudoku(int matrix[SIZE][SIZE]) {
+	int row,num;
+    for (row = 0; row < SIZE; row++) {
+        for (num = 1; num <= 9; num++) {
+            if (!checkRow(matrix, row, num)) {
+                sprintf(errorMessage, "The number %d in the row %d has been used!", num, row + 1);
+                return false;
+            }
+        }
+    }
+    int col;
+    for (col = 0; col < SIZE; col++) {
+        for (num = 1; num <= 9; num++) {
+            if (!checkCol(matrix, col, num)) {
+                sprintf(errorMessage, "The number %d in the col %d has been used!", num, col + 1);
+                return false;
+            }
+        }
+    }
+    int startRow,startCol;
+    for (startRow = 0; startRow < SIZE; startRow += 3) {
+        for (startCol = 0; startCol < SIZE; startCol += 3) {
+            for (num = 1; num <= 9; num++) {
+                if (!checkBlock(matrix, startRow, startCol, num)) {
+                    sprintf(errorMessage, "The number %d in the block %d has been used!", num, (startRow / 3) * 3 + startCol / 3 + 1);
+                    return false;
+                }
+            }
+        }
+    }
+    return true;
+}
+bool checkRow(int matrix[SIZE][SIZE], int row, int num) {
+    int count = 0,col;
+    for (col = 0; col < SIZE; col++) {
+        if (matrix[row][col] == num) count++;
+        if (count > 1) {
+            return false;
+        }
+    }
+    return true;
+}
+bool checkCol(int matrix[SIZE][SIZE], int col, int num) {
+    int count = 0,row;
+    for (row = 0; row < SIZE; row++) {
+        if (matrix[row][col] == num) count++;
+        if (count > 1) {
+            return false;
+        }
+    }
+    return true;
+}
+bool checkBlock(int matrix[SIZE][SIZE], int startRow, int startCol, int num) {
+    int count = 0,row,col;
+    for (row = 0; row < 3; row++) {
+        for (col = 0; col < 3; col++) {
+            if (matrix[startRow + row][startCol + col] == num) count++;
+            if (count > 1) {
+                return false;
+            }
+        }
+    }
+    return true;
+}