Run-length encoding compresses data by replacing each consecutive run of equal values with the value and the number of times it appears. It is effective for repetitive data in columnar databases, bitmap indexes, and image formats.
Design a RunLengthEncoder class:
RunLengthEncoder() creates a stateless encoder.int[] encode(int[] data) returns a flattened run-length encoding in the form [value1, count1, value2, count2, ...].
Runs are based on consecutive values. Equal values separated by another value belong to different runs. A run of length one still emits its value followed by 1. Return an empty array when data is empty, and do not modify data.
Example 1:
Input:
Output:
Explanation: Three 1s become [1,3], two 2s become [2,2], and the single 3 becomes [3,1].
Example 2:
Input:
Output:
Explanation: The two groups of 7s stay separate because the three 8s split them into different runs.
Constraints
0 <= data.length <= 10^5-10^9 <= data[i] <= 10^9- The output contains one value-count pair for every maximal run.
- At most
100 calls are made to encode.
Run-Length Encode Dataeasy