feat: add weekly contest 470

solution/0400-0499/0417.Pacific Atlantic Water Flow/README_EN.md

@@ -34,19 +34,19 @@ tags:
 <strong>Input:</strong> heights = [[1,2,2,3,5],[3,2,3,4,4],[2,4,5,3,1],[6,7,1,4,5],[5,1,1,2,4]]
 <strong>Output:</strong> [[0,4],[1,3],[1,4],[2,2],[3,0],[3,1],[4,0]]
 <strong>Explanation:</strong> The following cells can flow to the Pacific and Atlantic oceans, as shown below:
-[0,4]: [0,4] -&gt; Pacific Ocean
+[0,4]: [0,4] -&gt; Pacific Ocean 
 &nbsp;      [0,4] -&gt; Atlantic Ocean
-[1,3]: [1,3] -&gt; [0,3] -&gt; Pacific Ocean
+[1,3]: [1,3] -&gt; [0,3] -&gt; Pacific Ocean 
 &nbsp;      [1,3] -&gt; [1,4] -&gt; Atlantic Ocean
-[1,4]: [1,4] -&gt; [1,3] -&gt; [0,3] -&gt; Pacific Ocean
+[1,4]: [1,4] -&gt; [1,3] -&gt; [0,3] -&gt; Pacific Ocean 
 &nbsp;      [1,4] -&gt; Atlantic Ocean
-[2,2]: [2,2] -&gt; [1,2] -&gt; [0,2] -&gt; Pacific Ocean
+[2,2]: [2,2] -&gt; [1,2] -&gt; [0,2] -&gt; Pacific Ocean 
 &nbsp;      [2,2] -&gt; [2,3] -&gt; [2,4] -&gt; Atlantic Ocean
-[3,0]: [3,0] -&gt; Pacific Ocean
+[3,0]: [3,0] -&gt; Pacific Ocean 
 &nbsp;      [3,0] -&gt; [4,0] -&gt; Atlantic Ocean
-[3,1]: [3,1] -&gt; [3,0] -&gt; Pacific Ocean
+[3,1]: [3,1] -&gt; [3,0] -&gt; Pacific Ocean 
 &nbsp;      [3,1] -&gt; [4,1] -&gt; Atlantic Ocean
-[4,0]: [4,0] -&gt; Pacific Ocean
+[4,0]: [4,0] -&gt; Pacific Ocean 
        [4,0] -&gt; Atlantic Ocean
 Note that there are other possible paths for these cells to flow to the Pacific and Atlantic oceans.
 </pre>

solution/3600-3699/3692.Majority Frequency Characters/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 简单
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3692.Majority%20Frequency%20Characters/README.md
+rating: 1384
+source: 第 166 场双周赛 Q1
 ---
 
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solution/3600-3699/3692.Majority Frequency Characters/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Easy
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3692.Majority%20Frequency%20Characters/README_EN.md
+rating: 1384
+source: Biweekly Contest 166 Q1
 ---
 
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solution/3600-3699/3693.Climbing Stairs II/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 中等
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3693.Climbing%20Stairs%20II/README.md
+rating: 1560
+source: 第 166 场双周赛 Q2
 ---
 
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solution/3600-3699/3693.Climbing Stairs II/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Medium
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3693.Climbing%20Stairs%20II/README_EN.md
+rating: 1560
+source: Biweekly Contest 166 Q2
 ---
 
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solution/3600-3699/3694.Distinct Points Reachable After Substring Removal/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 中等
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3694.Distinct%20Points%20Reachable%20After%20Substring%20Removal/README.md
+rating: 1739
+source: 第 166 场双周赛 Q3
 ---
 
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solution/3600-3699/3694.Distinct Points Reachable After Substring Removal/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Medium
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3694.Distinct%20Points%20Reachable%20After%20Substring%20Removal/README_EN.md
+rating: 1739
+source: Biweekly Contest 166 Q3
 ---
 
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solution/3600-3699/3695.Maximize Alternating Sum Using Swaps/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 困难
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3695.Maximize%20Alternating%20Sum%20Using%20Swaps/README.md
+rating: 1984
+source: 第 166 场双周赛 Q4
 ---
 
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solution/3600-3699/3695.Maximize Alternating Sum Using Swaps/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Hard
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3695.Maximize%20Alternating%20Sum%20Using%20Swaps/README_EN.md
+rating: 1984
+source: Biweekly Contest 166 Q4
 ---
 
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solution/3600-3699/3697.Compute Decimal Representation/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 简单
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3697.Compute%20Decimal%20Representation/README.md
+rating: 1250
+source: 第 469 场周赛 Q1
 ---
 
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solution/3600-3699/3697.Compute Decimal Representation/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Easy
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3697.Compute%20Decimal%20Representation/README_EN.md
+rating: 1250
+source: Weekly Contest 469 Q1
 ---
 
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solution/3600-3699/3698.Split Array With Minimum Difference/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 中等
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3698.Split%20Array%20With%20Minimum%20Difference/README.md
+rating: 1648
+source: 第 469 场周赛 Q2
 ---
 
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solution/3600-3699/3698.Split Array With Minimum Difference/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Medium
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3698.Split%20Array%20With%20Minimum%20Difference/README_EN.md
+rating: 1648
+source: Weekly Contest 469 Q2
 ---
 
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solution/3600-3699/3699.Number of ZigZag Arrays I/README.md

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 comments: true
 difficulty: 困难
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3699.Number%20of%20ZigZag%20Arrays%20I/README.md
+rating: 2123
+source: 第 469 场周赛 Q3
 ---
 
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solution/3600-3699/3699.Number of ZigZag Arrays I/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Hard
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3600-3699/3699.Number%20of%20ZigZag%20Arrays%20I/README_EN.md
+rating: 2123
+source: Weekly Contest 469 Q3
 ---
 
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solution/3700-3799/3700.Number of ZigZag Arrays II/README.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: 困难
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3700-3799/3700.Number%20of%20ZigZag%20Arrays%20II/README.md
+rating: 2435
+source: 第 469 场周赛 Q4
 ---
 
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solution/3700-3799/3700.Number of ZigZag Arrays II/README_EN.md

@@ -2,6 +2,8 @@
 comments: true
 difficulty: Hard
 edit_url: https://github.com/doocs/leetcode/edit/main/solution/3700-3799/3700.Number%20of%20ZigZag%20Arrays%20II/README_EN.md
+rating: 2435
+source: Weekly Contest 469 Q4
 ---
 
 <!-- problem:start -->

solution/3700-3799/3701.Compute Alternating Sum/README.md

@@ -0,0 +1,150 @@
+---
+comments: true
+difficulty: 简单
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/3700-3799/3701.Compute%20Alternating%20Sum/README.md
+---
+
+<!-- problem:start -->
+
+# [3701. 计算交替和](https://leetcode.cn/problems/compute-alternating-sum)
+
+[English Version](/solution/3700-3799/3701.Compute%20Alternating%20Sum/README_EN.md)
+
+## 题目描述
+
+<!-- description:start -->
+
+<p>给你一个整数数组 <code>nums</code>。</p>
+
+<p><strong>交替和&nbsp;</strong>定义为：将 <code>nums</code> 中偶数下标位置的元素&nbsp;<strong>相加&nbsp;</strong>，<strong>减去</strong> 奇数下标位置的元素。即：<code>nums[0] - nums[1] + nums[2] - nums[3]...</code></p>
+
+<p>返回表示 <code>nums</code> 的交替和的整数。</p>
+
+<p>&nbsp;</p>
+
+<p><strong class="example">示例 1：</strong></p>
+
+<div class="example-block">
+<p><strong>输入：</strong> <span class="example-io">nums = [1,3,5,7]</span></p>
+
+<p><strong>输出：</strong> <span class="example-io">-4</span></p>
+
+<p><strong>解释：</strong></p>
+
+<ul>
+	<li>偶数下标位置的元素是 <code>nums[0] = 1</code> 和 <code>nums[2] = 5</code>，因为 0 和 2 是偶数。</li>
+	<li>奇数下标位置的元素是 <code>nums[1] = 3</code> 和 <code>nums[3] = 7</code>，因为 1 和 3 是奇数。</li>
+	<li>交替和为 <code>nums[0] - nums[1] + nums[2] - nums[3] = 1 - 3 + 5 - 7 = -4</code>。</li>
+</ul>
+</div>
+
+<p><strong class="example">示例 2：</strong></p>
+
+<div class="example-block">
+<p><strong>输入：</strong> <span class="example-io">nums = [100]</span></p>
+
+<p><strong>输出：</strong> <span class="example-io">100</span></p>
+
+<p><strong>解释：</strong></p>
+
+<ul>
+	<li>唯一的偶数下标位置的元素是 <code>nums[0] = 100</code>，因为 0 是偶数。</li>
+	<li>没有奇数下标位置的元素。</li>
+	<li>交替和为 <code>nums[0] = 100</code>。</li>
+</ul>
+</div>
+
+<p>&nbsp;</p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 100</code></li>
+	<li><code>1 &lt;= nums[i] &lt;= 100</code></li>
+</ul>
+
+<!-- description:end -->
+
+## 解法
+
+<!-- solution:start -->
+
+### 方法一：模拟
+
+我们可以直接遍历数组 $\textit{nums}$，对于每个下标 $i$，如果 $i$ 是偶数，则将 $\textit{nums}[i]$ 加到答案中，否则将 $\textit{nums}[i]$ 减去。
+
+最后返回答案即可。
+
+时间复杂度 $O(n)$，其中 $n$ 是数组 $\textit{nums}$ 的长度。空间复杂度 $O(1)$。
+
+<!-- tabs:start -->
+
+#### Python3
+
+```python
+class Solution:
+    def alternatingSum(self, nums: List[int]) -> int:
+        return sum(nums[0::2]) - sum(nums[1::2])
+```
+
+#### Java
+
+```java
+class Solution {
+    public int alternatingSum(int[] nums) {
+        int ans = 0;
+        for (int i = 0; i < nums.length; ++i) {
+            ans += (i % 2 == 0 ? nums[i] : -nums[i]);
+        }
+        return ans;
+    }
+}
+```
+
+#### C++
+
+```cpp
+class Solution {
+public:
+    int alternatingSum(vector<int>& nums) {
+        int ans = 0;
+        for (int i = 0; i < nums.size(); ++i) {
+            ans += (i % 2 == 0 ? nums[i] : -nums[i]);
+        }
+        return ans;
+    }
+};
+```
+
+#### Go
+
+```go
+func alternatingSum(nums []int) (ans int) {
+	for i, x := range nums {
+		if i%2 == 0 {
+			ans += x
+		} else {
+			ans -= x
+		}
+	}
+	return
+}
+```
+
+#### TypeScript
+
+```ts
+function alternatingSum(nums: number[]): number {
+    let ans: number = 0;
+    for (let i = 0; i < nums.length; ++i) {
+        ans += i % 2 === 0 ? nums[i] : -nums[i];
+    }
+    return ans;
+}
+```
+
+<!-- tabs:end -->
+
+<!-- solution:end -->
+
+<!-- problem:end -->