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3001-3100/3016. Minimum Number of Pushes to Type Word II.md
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# 3016. Minimum Number of Pushes to Type Word II | ||
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- Difficulty: Medium. | ||
- Related Topics: Hash Table, String, Greedy, Sorting, Counting. | ||
- Similar Questions: Letter Combinations of a Phone Number. | ||
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## Problem | ||
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You are given a string `word` containing lowercase English letters. | ||
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Telephone keypads have keys mapped with **distinct** collections of lowercase English letters, which can be used to form words by pushing them. For example, the key `2` is mapped with `["a","b","c"]`, we need to push the key one time to type `"a"`, two times to type `"b"`, and three times to type `"c"` **.** | ||
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It is allowed to remap the keys numbered `2` to `9` to **distinct** collections of letters. The keys can be remapped to **any** amount of letters, but each letter **must** be mapped to **exactly** one key. You need to find the **minimum** number of times the keys will be pushed to type the string `word`. | ||
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Return **the **minimum** number of pushes needed to type **`word` **after remapping the keys**. | ||
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An example mapping of letters to keys on a telephone keypad is given below. Note that `1`, `*`, `#`, and `0` do **not** map to any letters. | ||
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![](https://assets.leetcode.com/uploads/2023/12/26/keypaddesc.png) | ||
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Example 1: | ||
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![](https://assets.leetcode.com/uploads/2023/12/26/keypadv1e1.png) | ||
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``` | ||
Input: word = "abcde" | ||
Output: 5 | ||
Explanation: The remapped keypad given in the image provides the minimum cost. | ||
"a" -> one push on key 2 | ||
"b" -> one push on key 3 | ||
"c" -> one push on key 4 | ||
"d" -> one push on key 5 | ||
"e" -> one push on key 6 | ||
Total cost is 1 + 1 + 1 + 1 + 1 = 5. | ||
It can be shown that no other mapping can provide a lower cost. | ||
``` | ||
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Example 2: | ||
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![](https://assets.leetcode.com/uploads/2023/12/26/keypadv2e2.png) | ||
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``` | ||
Input: word = "xyzxyzxyzxyz" | ||
Output: 12 | ||
Explanation: The remapped keypad given in the image provides the minimum cost. | ||
"x" -> one push on key 2 | ||
"y" -> one push on key 3 | ||
"z" -> one push on key 4 | ||
Total cost is 1 * 4 + 1 * 4 + 1 * 4 = 12 | ||
It can be shown that no other mapping can provide a lower cost. | ||
Note that the key 9 is not mapped to any letter: it is not necessary to map letters to every key, but to map all the letters. | ||
``` | ||
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Example 3: | ||
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![](https://assets.leetcode.com/uploads/2023/12/27/keypadv2.png) | ||
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``` | ||
Input: word = "aabbccddeeffgghhiiiiii" | ||
Output: 24 | ||
Explanation: The remapped keypad given in the image provides the minimum cost. | ||
"a" -> one push on key 2 | ||
"b" -> one push on key 3 | ||
"c" -> one push on key 4 | ||
"d" -> one push on key 5 | ||
"e" -> one push on key 6 | ||
"f" -> one push on key 7 | ||
"g" -> one push on key 8 | ||
"h" -> two pushes on key 9 | ||
"i" -> one push on key 9 | ||
Total cost is 1 * 2 + 1 * 2 + 1 * 2 + 1 * 2 + 1 * 2 + 1 * 2 + 1 * 2 + 2 * 2 + 6 * 1 = 24. | ||
It can be shown that no other mapping can provide a lower cost. | ||
``` | ||
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**Constraints:** | ||
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- `1 <= word.length <= 105` | ||
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- `word` consists of lowercase English letters. | ||
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## Solution | ||
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```javascript | ||
/** | ||
* @param {string} word | ||
* @return {number} | ||
*/ | ||
var minimumPushes = function(word) { | ||
var frequencyMap = Array(26).fill(0); | ||
var a = 'a'.charCodeAt(0); | ||
for (var i = 0; i < word.length; i++) { | ||
frequencyMap[word[i].charCodeAt(0) - a] += 1; | ||
} | ||
var arr = frequencyMap.sort((a, b) => b - a); | ||
var res = 0; | ||
for (var i = 0; i < arr.length; i++) { | ||
res += Math.ceil((i + 1) / 8) * arr[i]; | ||
} | ||
return res; | ||
}; | ||
``` | ||
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**Explain:** | ||
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nope. | ||
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**Complexity:** | ||
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* Time complexity : O(n). | ||
* Space complexity : O(1). |