一刷2320

Author: diguage

README.adoc

@@ -16266,12 +16266,12 @@ TIP: **公众号的微信号是: `jikerizhi`**。__因为众所周知的原因
 //|Easy
 //|
 
-//|{counter:codes}
-//|{leetcode_base_url}/count-number-of-ways-to-place-houses/[2320. Count Number of Ways to Place Houses^]
-//|{source_base_url}/_2320_CountNumberOfWaysToPlaceHouses.java[Java]
-//|{doc_base_url}/2320-count-number-of-ways-to-place-houses.adoc[题解]
-//|Medium
-//|
+|{counter:codes}
+|{leetcode_base_url}/count-number-of-ways-to-place-houses/[2320. Count Number of Ways to Place Houses^]
+|{source_base_url}/_2320_CountNumberOfWaysToPlaceHouses.java[Java]
+|{doc_base_url}/2320-count-number-of-ways-to-place-houses.adoc[题解]
+|Medium
+|
 
 //|{counter:codes}
 //|{leetcode_base_url}/maximum-score-of-spliced-array/[2321. Maximum Score Of Spliced Array^]

docs/2320-count-number-of-ways-to-place-houses.adoc

@@ -1,49 +1,47 @@
 [#2320-count-number-of-ways-to-place-houses]
-= 2320. Count Number of Ways to Place Houses
+= 2320. 统计放置房子的方式数
 
-{leetcode}/problems/count-number-of-ways-to-place-houses/[LeetCode - 2320. Count Number of Ways to Place Houses ^]
+https://leetcode.cn/problems/count-number-of-ways-to-place-houses/[LeetCode - 2320. 统计放置房子的方式数 ^]
 
-There is a street with `n * 2` *plots*, where there are `n` plots on each side of the street. The plots on each side are numbered from `1` to `n`. On each plot, a house can be placed.
+一条街道上共有 `n * 2` 个 *地块* ，街道的两侧各有 `n` 个地块。每一边的地块都按从 `1` 到 `n` 编号。每个地块上都可以放置一所房子。
 
-Return _the number of ways houses can be placed such that no two houses are adjacent to each other on the same side of the street_. Since the answer may be very large, return it *modulo* `10^9^ + 7`.
+现要求街道同一侧不能存在两所房子相邻的情况，请你计算并返回放置房屋的方式数目。由于答案可能很大，需要对 `10^9^ + 7` 取余后再返回。
 
-Note that if a house is placed on the `i^th^` plot on one side of the street, a house can also be placed on the `i^th^` plot on the other side of the street.
+注意，如果一所房子放置在这条街某一侧上的第 `i` 个地块，不影响在另一侧的第 `i` 个地块放置房子。
 
- 
-*Example 1:*
+*示例 1：*
 
-[subs="verbatim,quotes"]
-----
-*Input:* n = 1
-*Output:* 4
-*Explanation:* 
-Possible arrangements:
-1. All plots are empty.
-2. A house is placed on one side of the street.
-3. A house is placed on the other side of the street.
-4. Two houses are placed, one on each side of the street.
-----
+....
+输入：n = 1
+输出：4
+解释：
+可能的放置方式：
+1. 所有地块都不放置房子。
+2. 一所房子放在街道的某一侧。
+3. 一所房子放在街道的另一侧。
+4. 放置两所房子，街道两侧各放置一所。
+....
 
-*Example 2:*
-<img alt="" src="https://assets.leetcode.com/uploads/2022/05/12/arrangements.png" style="width: 500px; height: 500px;" />
-[subs="verbatim,quotes"]
-----
-*Input:* n = 2
-*Output:* 9
-*Explanation:* The 9 possible arrangements are shown in the diagram above.
-----
+*示例 2：*
 
- 
-*Constraints:*
+image::images/2320-01.png[{image_attr}]
 
+....
+输入：n = 2
+输出：9
+解释：如上图所示，共有 9 种可能的放置方式。
+....
 
-* `1 <= n <= 10^4^`
-
+*提示：*
 
+* `1 \<= n \<= 10^4^`
 
 
 == 思路分析
 
+先只考虑一边的情况，再组合两边的情况。只考虑一边的情况，就是一个斐波那契数列： stem:[f(i) = f(i-1) + f(i-2)]。
+
+另外，需要注意处理余数问题。
 
 [[src-2320]]
 [tabs]
@@ -70,4 +68,4 @@ include::{sourcedir}/_2320_CountNumberOfWaysToPlaceHouses.java[tag=answer]
 
 == 参考资料
 
-
+. https://leetcode.cn/problems/count-number-of-ways-to-place-houses/solutions/1625979/d-by-endlesscheng-gybx/[2320. 统计放置房子的方式数 - 线性 DP^]

docs/images/2320-01.png

@@ -4724,7 +4724,7 @@ include::1997-first-day-where-you-have-been-in-all-the-rooms.adoc[leveloffset=+1
 
 // include::2319-check-if-matrix-is-x-matrix.adoc[leveloffset=+1]
 
-// include::2320-count-number-of-ways-to-place-houses.adoc[leveloffset=+1]
+include::2320-count-number-of-ways-to-place-houses.adoc[leveloffset=+1]
 
 // include::2321-maximum-score-of-spliced-array.adoc[leveloffset=+1]
 

docs/index.adoc

@@ -653,6 +653,11 @@ endif::[]
 |{doc_base_url}/2800-shortest-string-that-contains-three-strings.adoc[题解]
 |❌ 先求三个字符串的全排列，然后合并（合并时注意处理首尾相同子串，减少合并字符串的长度），在这些合并后的字符串中选择最短，字典排序最小的字符串。
 
+|{counter:codes2503}
+|{leetcode_base_url}/count-number-of-ways-to-place-houses/[2320. 统计放置房子的方式数^]
+|{doc_base_url}/2320-count-number-of-ways-to-place-houses.adoc[题解]
+|❌ 先只考虑一边的情况，再组合两边的情况。只考虑一边的情况，就是一个斐波那契数列： stem:[f(i) = f(i-1) + f(i-2)]。
+
 |===
 
 截止目前，本轮练习一共完成 {codes2503} 道题。

logbook/202503.adoc

@@ -0,0 +1,24 @@
+package com.diguage.algo.leetcode;
+
+public class _2320_CountNumberOfWaysToPlaceHouses {
+  // tag::answer[]
+  /**
+   * @author D瓜哥 · https://www.diguage.com
+   * @since 2025-05-11 19:24:20
+   */
+  public int countHousePlacements(int n) {
+    long a = 1, b = 2;
+    long cnt = b;
+    for (int i = 2; i <= n; i++) {
+      cnt = (a + b) % 1_000_000_007;
+      a = b;
+      b = cnt;
+    }
+    return (int) ((cnt * cnt) % 1_000_000_007);
+  }
+  // end::answer[]
+  public static void main(String[] args) {
+    new _2320_CountNumberOfWaysToPlaceHouses()
+      .countHousePlacements(1000);
+  }
+}