LeetCode-1313 Decompress Run-Length Encoded List solutions (with Java and python)

1. Description:

 Notes:

 2. Examples:

 3.Solutions:

 Java Version 1:

/**
 * @author sheepcore
 * created on 2020-03-02
 */ 
public int[] decompressRLElist(int[] nums) {
        int[] res = new int[100000];
        int size = 0;
        for(int i = 0; i < nums.length; i += 2) {
            int freq = nums[i];
            int val = nums[i + 1];
            for(int j = 0; j < freq; j++) {
                res[size++] = val;
            }
        }
        return Arrays.copyOf(res, size);
}

Java Version 2:

/**
 * @author sheepcore
 * created on 2020-03-02
 */
public int[] decompressRLElistV2(int[] nums) {
    List<Integer> res = new ArrayList<>();
    for(int i = 0; i < nums.length; i += 2) {
        int freq = nums[i];
        int val = nums[i+1];
        while(freq-- != 0) {
            res.add(val);
        }
    }
    int[] outputs = new int[res.size()];
    for(int i = 0; i < res.size(); i++) {
        outputs[i] = res.get(i);
    }
    return outputs;
}

One-line Python Version:

"""
    created by lee215 
"""
def decompressRLElist(self, A):
        return [x for a, b in zip(A[0::2], A[1::2]) for x in [b] * a]

4. Summary:

• Java 中如何完成数组的复制 Arrays.copyOf(int[] origin, int newLength)

• python 中 zip 的使用