if unique_id's are equal then compare current row end value with next row start in pandas dataframe

Question

data = [
[\'30\', \'12\', \'42\'],
[\'30\',\'30\',\'100\'],
[\'10\', \'70\',\'300\'],
[\'10\',\'200\',\'700\'],
[\'20\',\'800\',\'900\'],
[\'20\',\'600\',\'1000\'],