{ "data": { "question": { "questionId": "2191", "questionFrontendId": "2086", "categoryTitle": "Algorithms", "boundTopicId": 1121117, "title": "Minimum Number of Buckets Required to Collect Rainwater from Houses", "titleSlug": "minimum-number-of-buckets-required-to-collect-rainwater-from-houses", "content": "

You are given a 0-indexed string street. Each character in street is either 'H' representing a house or '.' representing an empty space.

\n\n

You can place buckets on the empty spaces to collect rainwater that falls from the adjacent houses. The rainwater from a house at index i is collected if a bucket is placed at index i - 1 and/or index i + 1. A single bucket, if placed adjacent to two houses, can collect the rainwater from both houses.

\n\n

Return the minimum number of buckets needed so that for every house, there is at least one bucket collecting rainwater from it, or -1 if it is impossible.

\n\n

 

\n

Example 1:

\n\n
\nInput: street = "H..H"\nOutput: 2\nExplanation:\nWe can put buckets at index 1 and index 2.\n"H..H" -> "HBBH" ('B' denotes where a bucket is placed).\nThe house at index 0 has a bucket to its right, and the house at index 3 has a bucket to its left.\nThus, for every house, there is at least one bucket collecting rainwater from it.\n
\n\n

Example 2:

\n\n
\nInput: street = ".H.H."\nOutput: 1\nExplanation:\nWe can put a bucket at index 2.\n".H.H." -> ".HBH." ('B' denotes where a bucket is placed).\nThe house at index 1 has a bucket to its right, and the house at index 3 has a bucket to its left.\nThus, for every house, there is at least one bucket collecting rainwater from it.\n
\n\n

Example 3:

\n\n
\nInput: street = ".HHH."\nOutput: -1\nExplanation:\nThere is no empty space to place a bucket to collect the rainwater from the house at index 2.\nThus, it is impossible to collect the rainwater from all the houses.\n
\n\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "从房屋收集雨水需要的最少水桶数", "translatedContent": "

给你一个下标从 0 开始的字符串 street 。street 中每个字符要么是表示房屋的 'H' ，要么是表示空位的 '.' 。

\n\n

你可以在 空位 放置水桶，从相邻的房屋收集雨水。位置在 i - 1 或者 i + 1 的水桶可以收集位置为 i 处房屋的雨水。一个水桶如果相邻两个位置都有房屋，那么它可以收集 两个 房屋的雨水。

\n\n

在确保 每个 房屋旁边都 至少 有一个水桶的前提下，请你返回需要的 最少 水桶数。如果无解请返回 -1 。

\n\n

 

\n\n

示例 1：

\n\n
输入：street = \"H..H\"\n输出：2\n解释：\n我们可以在下标为 1 和 2 处放水桶。\n\"H..H\" -> \"HBBH\"（'B' 表示放置水桶）。\n下标为 0 处的房屋右边有水桶，下标为 3 处的房屋左边有水桶。\n所以每个房屋旁边都至少有一个水桶收集雨水。\n
\n\n

示例 2：

\n\n
输入：street = \".H.H.\"\n输出：1\n解释：\n我们可以在下标为 2 处放置一个水桶。\n\".H.H.\" -> \".HBH.\"（'B' 表示放置水桶）。\n下标为 1 处的房屋右边有水桶，下标为 3 处的房屋左边有水桶。\n所以每个房屋旁边都至少有一个水桶收集雨水。\n
\n\n

示例 3：

\n\n
输入：street = \".HHH.\"\n输出：-1\n解释：\n没有空位可以放置水桶收集下标为 2 处的雨水。\n所以没有办法收集所有房屋的雨水。\n
\n\n

示例 4：

\n\n
输入：street = \"H\"\n输出：-1\n解释：\n没有空位放置水桶。\n所以没有办法收集所有房屋的雨水。\n
\n\n

示例 5：

\n\n
输入：street = \".\"\n输出：0\n解释：\n没有房屋需要收集雨水。\n所以需要 0 个水桶。\n
\n\n

 

\n\n

提示：

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