add cplusplus version in shell-sort and merg-sort

Author: shouao

4.shellSort.md

@@ -144,3 +144,23 @@ function shellSort($arr)
     return $arr;
 }
 ```
+
+## 7. C++ 代码实现
+
+```cpp
+void shellSort(vector<int>& nums) {
+    int gap = 1;
+    while (gap < (int)nums.size() / 3) {
+    	gap = gap * 3 + 1;
+    }
+	for (; gap >= 1; gap /= 3) {
+		for (int i = 0; i < gap; ++i) {
+			for (int j = i + gap; j < nums.size(); j += gap) {
+				for (int k = j; k - gap >= 0 && nums[k] < nums[k - gap]; k -= gap) {
+                	swap(nums[k], nums[k - gap]);
+                }
+            }
+        }
+    }
+}
+```

5.mergeSort.md

@@ -222,4 +222,69 @@ function merge($left, $right)
 
     return $result;
 }
+```
+
+## 9. C++ 代码实现
+
+### 9.1 递归版
+
+```cpp
+void mergeSort(vector<int>& nums, int l, int r) {
+    if (r - l <= 1) {
+       return;
+    }
+    int mid = (l + r) / 2;
+    mergeSort(nums, l, mid);
+    mergeSort(nums, mid, r);
+    int index = 0;
+    int ptrL = l;
+    int ptrR = mid;
+    static vector<int>tempary(50000);
+    while (ptrL != mid && ptrR != r) {
+        if (nums[ptrL] < nums[ptrR]) {
+            tempary[index++] = nums[ptrL++];
+        } else {
+            tempary[index++] = nums[ptrR++];
+        }
+    }
+    while (ptrL != mid) {
+        tempary[index++] = nums[ptrL++];
+    }
+    while (ptrR != r) {
+       tempary[index++] = nums[ptrR++];
+    }
+    copy(tempary.begin(), tempary.begin() + index, nums.begin() + l);
+}
+```
+
+### 9.2 迭代版
+
+```cpp
+void mergeSort(vector<int>& nums) {
+    for (int step = 1; step <= nums.size(); step *= 2) {
+        for (int i = 0; i + step < nums.size(); i += 2 * step) {
+            int l = i;
+            int r = min((int)nums.size(), i + step * 2);
+            int mid = i + step;
+            int index = 0;
+            int ptrL = l;
+            int ptrR = mid;
+            static vector<int>tempary(50000);
+            while (ptrL != mid && ptrR != r) {
+                if (nums[ptrL] < nums[ptrR]) {
+               		tempary[index++] = nums[ptrL++];
+                } else {
+                	tempary[index++] = nums[ptrR++];
+                }
+            }
+            while (ptrL != mid) {
+            	tempary[index++] = nums[ptrL++];
+            }
+            while (ptrR != r) {
+            	tempary[index++] = nums[ptrR++];
+            }
+            copy(tempary.begin(), tempary.begin() + index, nums.begin() + l);
+        }
+    }
+}
 ```