String Compression: coding question

Problem

You get an array of characters chars. Compress the array in place. First, split chars into groups. A group is a sequence of equal characters that are next to each other.

For each group, write the character. If the group has more than one character, write the group length after the character. A length of 10 or more uses one item for each digit.

Write the compressed result at the start of chars, and return its length. The items after this length do not matter. Use only O(1) extra space.

In the examples, the output shows the returned length and then the first part of chars with this length.

Example 1

Input:: chars = ["x","x","x","y","z","z"]
Output:: [5,["x","3","y","z","2"]]
Explanation:: The groups are xxx, y and zz. The group y has one character, so no number follows it.

Example 2

Input:: chars = ["m","m","m","m","m","m","m","m","m","m","m","m","n","n"]
Output:: [5,["m","1","2","n","2"]]
Explanation:: The group of m characters has length 12. The digits 1 and 2 use one item each.

Example 3

Input:: chars = ["q"]
Output:: [1,["q"]]

Constraints

1 <= chars.length <= 2000
chars[i] is a lowercase English letter, an uppercase English letter, a digit or a symbol.

SysRound wrote this statement. A reference solution checks every example.

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LeetCode 443. String Compression
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String Compression
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Problem

You get an array of characters chars. Compress the array in place. First, split chars into groups. A group is a sequence of equal characters that are next to each other.

For each group, write the character. If the group has more than one character, write the group length after the character. A length of 10 or more uses one item for each digit.

Write the compressed result at the start of chars, and return its length. The items after this length do not matter. Use only O(1) extra space.

In the examples, the output shows the returned length and then the first part of chars with this length.

Example 1

Input:: chars = ["x","x","x","y","z","z"]
Output:: [5,["x","3","y","z","2"]]
Explanation:: The groups are xxx, y and zz. The group y has one character, so no number follows it.

Example 2

Input:: chars = ["m","m","m","m","m","m","m","m","m","m","m","m","n","n"]
Output:: [5,["m","1","2","n","2"]]
Explanation:: The group of m characters has length 12. The digits 1 and 2 use one item each.

Example 3

Input:: chars = ["q"]
Output:: [1,["q"]]

Constraints

1 <= chars.length <= 2000
chars[i] is a lowercase English letter, an uppercase English letter, a digit or a symbol.

SysRound wrote this statement. A reference solution checks every example.

String Compression

Problem

Example 1

Example 2

Example 3

Constraints

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String Compression

Problem

Example 1

Example 2

Example 3

Constraints

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