Утро жителей Харькова началось со взрывов08:46
СюжетВзрывы в США:。体育直播对此有专业解读
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this isn’t just an academic curiosity. flip the alternation order to (ab|a)+ and suddenly PCRE matches the entire string! the | operator in backtracking engines is ordered - it’s not union, it’s “try left first”. the order of branches changes the result, which means | is not commutative. a|b and b|a can give different matches.