diff --git a/T4new.cpp b/T4new.cpp
new file mode 100644
index 0000000..cc421bd
--- /dev/null
+++ b/T4new.cpp
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdbool.h>
+#define N 9
+void printSudoku(int sudoku[9][9]) {
+    printf("+-------+-------+-------+\n");
+    for (int i = 0; i < 9; i++) {
+        if (i > 0 && i % 3 == 0) {
+            printf("+-------+-------+-------+\n");
+        }
+        for (int j = 0; j < 9; j++) {
+            if (j % 3 == 0) {
+                printf("| ");
+            }
+            printf("%d ", sudoku[i][j]); // 输出数组中的元素
+        }
+        printf("|\n");
+    }
+    printf("+-------+-------+-------+\n");
+}
+// Function to check if a number is already present in the row
+bool isSafeRow(int board[N][N], int row, int num) {
+    for (int col = 0; col < N; col++) {
+        if (board[row][col] == num) {
+            return false;
+        }
+    }
+    return true;
+}
+// Function to check if a number is already present in the column
+bool isSafeCol(int board[N][N], int col, int num) {
+    for (int row = 0; row < N; row++) {
+        if (board[row][col] == num) {
+            return false;
+        }
+    }
+    return true;
+}
+// Function to check if a number is already present in the 3x3 grid
+bool isSafeGrid(int board[N][N], int row, int col, int num) {
+    int startRow = row - (row % 3);
+    int startCol = col - (col % 3);
+    for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 3; j++) {
+            if (board[i + startRow][j + startCol] == num) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+bool isSafe(int board[N][N], int row, int col, int num) {
+    return isSafeRow(board, row, num) && isSafeCol(board, col, num) && isSafeGrid(board, row, col, num);
+}
+bool solveSudoku(int board[N][N]) {
+    int row = -1;
+    int col = -1;
+    bool isEmpty = true;
+    // Find an empty cell
+    for (int i = 0; i < N && isEmpty; i++) {
+        for (int j = 0; j < N && isEmpty; j++) {
+            if (board[i][j] == 0) {
+                row = i;
+                col = j;
+                isEmpty = false;
+            }
+        }
+    }
+    if (isEmpty) {
+        return true;
+    }
+    for (int num = 1; num <= N; num++) {
+        if (isSafe(board, row, col, num)) {
+            board[row][col] = num;
+
+            if (solveSudoku(board)) {
+                return true;
+            }
+
+            board[row][col] = 0;
+        }
+    }   return false;
+}
+int main() {
+    int sudoku[N][N] = {{5, 3, 0, 0, 7, 0, 0, 0, 0},
+{6, 0, 0, 1, 9, 5, 0, 0, 0},
+{0, 9, 8, 0, 0, 0, 0, 6, 0},
+{8, 0, 0, 0, 6, 0, 0, 0, 3},
+{4, 0, 0, 8, 0, 3, 0, 0, 1},
+{7, 0, 0, 0, 2, 0, 0, 0, 6},
+{0, 6, 0, 0, 0, 0, 2, 8, 0},
+{0, 0, 0, 4, 1, 9, 0, 0, 5},
+{0, 0, 0, 0, 8, 0, 0, 7, 9}
+    };
+    printf("The original Sudoku matrix:\n");
+    printSudoku(sudoku);
+    bool valid = solveSudoku(sudoku);
+    if (valid) {
+        printf("True: Valid initial Sudoku matrix!\n");
+
+        if (solveSudoku(sudoku)) {
+            printf("The solution of Sudoku matrix:\n");
+            printSudoku(sudoku);
+        } else {
+            printf("No solution!\n");
+        }
+    } else {
+        printf("False: Invalid initial Sudoku matrix!\n");
+        printf("No solution!\n");
+    }
+    return 0;
+}