Question

How to check if a string contains only valid parentheses (open close same type (), {}, []) in PHP

Answer 1

function string_contains_valid_parentheses($s) {
    $arr = array();
    
    foreach (str_split($s) as $ch) {
        if ($ch == '(') {
            array_unshift($arr, ')');
        }
        else if ($ch == '{') {
            array_unshift($arr, '}');
        }
        else if ($ch == '[') {
            array_unshift($arr, ']');
        }
        
        else if (empty($arr) || array_shift($arr) != $ch) {
            return false;
        }
    }
    
    return empty($stack);
}

echo string_contains_valid_parentheses("(){}[]()(){}") ? "true" : "false";



/*
run:

true

*/

 

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