we give list num integer represent list compress runlength encodingConsider adjacent pair element freq val nums2i nums2i1 0 for pair freq element value val concatenate sublist Concatenate sublist leave right generate decompress listReturn decompress list Example 1input num 1234output 2444explanation the pair 12 mean freq 1 val 2 generate array 2the second pair 34 mean freq 3 val 4 generate 444at end concatenation 2 444 2444example 2input num 1123output 133 constraints2 numslength 100numslength 2 01 numsi 100