diff --git "a/2101040022/chapter_7/\344\272\214\345\217\211\346\240\221\347\232\204\346\234\200\345\244\247\345\256\275\345\272\246.cpp" "b/2101040022/chapter_7/\344\272\214\345\217\211\346\240\221\347\232\204\346\234\200\345\244\247\345\256\275\345\272\246.cpp"
new file mode 100644
index 0000000000000000000000000000000000000000..0b435b1031e8abc8d109c664a951b4044516f886
--- /dev/null
+++ "b/2101040022/chapter_7/\344\272\214\345\217\211\346\240\221\347\232\204\346\234\200\345\244\247\345\256\275\345\272\246.cpp"
@@ -0,0 +1,38 @@
+#define MAX_NODE_SIZE 3000
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+typedef struct {
+    struct TreeNode *node;
+    unsigned long long index;
+} Pair;
+
+int widthOfBinaryTree(struct TreeNode* root){
+    unsigned long long res = 1;
+    Pair * arr = (Pair *)malloc(sizeof(Pair) * MAX_NODE_SIZE);
+    Pair * tmp = (Pair *)malloc(sizeof(Pair) * MAX_NODE_SIZE);
+    int arrSize = 0, tmpSize = 0;
+    arr[arrSize].node = root;
+    arr[arrSize].index = 1LL;
+    arrSize++;
+    while (arrSize > 0) {
+        tmpSize = 0;
+        for (int i = 0; i < arrSize; i++) {
+            if (arr[i].node->left) {
+                tmp[tmpSize].node = arr[i].node->left;
+                tmp[tmpSize].index = arr[i].index * 2;
+                tmpSize++;
+            }
+            if (arr[i].node->right) {
+                tmp[tmpSize].node = arr[i].node->right;
+                tmp[tmpSize].index = arr[i].index * 2 + 1;
+                tmpSize++;
+            }
+        }
+        res = MAX(res, arr[arrSize - 1].index - arr[0].index + 1);
+        arrSize = tmpSize;
+        Pair * p = arr;
+        arr = tmp;
+        tmp = p;
+    }
+    return res;
+}
\ No newline at end of file