diff --git a/website/content/ChapterFour/0700~0799/0747.Largest-Number-At-Least-Twice-of-Others.md b/website/content/ChapterFour/0700~0799/0747.Largest-Number-At-Least-Twice-of-Others.md
new file mode 100644
index 00000000..759e8cb7
--- /dev/null
+++ b/website/content/ChapterFour/0700~0799/0747.Largest-Number-At-Least-Twice-of-Others.md
@@ -0,0 +1,82 @@
+# [747. Largest Number At Least Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/)
+
+
+## 题目
+
+You are given an integer array `nums` where the largest integer is **unique**.
+
+Determine whether the largest element in the array is **at least twice** as much as every other number in the array. If it is, return *the **index** of the largest element, or return* `-1` *otherwise*.
+
+**Example 1:**
+
+```
+Input: nums = [3,6,1,0]
+Output: 1
+Explanation: 6 is the largest integer.
+For every other number in the array x, 6 is at least twice as big as x.
+The index of value 6 is 1, so we return 1.
+
+```
+
+**Example 2:**
+
+```
+Input: nums = [1,2,3,4]
+Output: -1
+Explanation: 4 is less than twice the value of 3, so we return -1.
+```
+
+**Example 3:**
+
+```
+Input: nums = [1]
+Output: 0
+Explanation: 1 is trivially at least twice the value as any other number because there are no other numbers.
+
+```
+
+**Constraints:**
+
+- `1 <= nums.length <= 50`
+- `0 <= nums[i] <= 100`
+- The largest element in `nums` is unique.
+
+## 题目大意
+
+给你一个整数数组 nums ，其中总是存在 唯一的 一个最大整数 。请你找出数组中的最大元素并检查它是否 至少是数组中每个其他数字的两倍 。如果是，则返回 最大元素的下标 ，否则返回 -1 。
+
+## 解题思路
+
+- 简单题。先扫描一遍找到最大值和下标。再扫描一遍检查最大值是否是其他数字的两倍。
+
+## 代码
+
+```go
+package leetcode
+
+func dominantIndex(nums []int) int {
+ maxNum, flag, index := 0, false, 0
+ for i, v := range nums {
+ if v > maxNum {
+ maxNum = v
+ index = i
+ }
+ }
+ for _, v := range nums {
+ if v != maxNum && 2*v > maxNum {
+ flag = true
+ }
+ }
+ if flag {
+ return -1
+ }
+ return index
+}
+```
+
+
+----------------------------------------------
+
diff --git a/website/content/ChapterFour/0700~0799/0748.Shortest-Completing-Word.md b/website/content/ChapterFour/0700~0799/0748.Shortest-Completing-Word.md
index 10f01707..54e53357 100755
--- a/website/content/ChapterFour/0700~0799/0748.Shortest-Completing-Word.md
+++ b/website/content/ChapterFour/0700~0799/0748.Shortest-Completing-Word.md
@@ -104,6 +104,6 @@ func match(lp [26]int, w string) bool {
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diff --git a/website/content/ChapterFour/0800~0899/0823.Binary-Trees-With-Factors.md b/website/content/ChapterFour/0800~0899/0823.Binary-Trees-With-Factors.md
index ce0ecf76..d58e146d 100644
--- a/website/content/ChapterFour/0800~0899/0823.Binary-Trees-With-Factors.md
+++ b/website/content/ChapterFour/0800~0899/0823.Binary-Trees-With-Factors.md
@@ -124,5 +124,5 @@ func numFactoredBinaryTrees1(arr []int) int {
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