✅ Regex Builder Approach
Solution\nswift []\nimport RegexBuilder\n\nstruct Solution {\n    @_optimize(speed)\n    func fractionAddition(_ expression: String) -> String {        \n      
# Solution\n```swift []\nimport RegexBuilder\n\nstruct Solution {\n    @_optimize(speed)\n    func fractionAddition(_ expression: String) -> String {        \n        let regex = Regex {\n            Capture {\n                Optionally("-")\n                OneOrMore(.digit)\n            }\n            "/"\n            Capture {\n                OneOrMore(.digit)\n            }\n        }\n\n        let fractions = expression\n            .matches(of: regex)\n            .compactMap { (Int($0.1) ?? 1, Int($0.2) ?? 1) }\n        var (num, denom) = (0, 1)\n\n        func gcd(_ x: Int, _ y: Int) -> Int {\n            x == 0 ? y : gcd(y % x, x)\n        }\n\n        for fraction in fractions {\n            let (cnum, cdenom) = fraction\n            num = num * cdenom + cnum * denom\n            denom *= cdenom\n            let common = abs(gcd(num, denom))\n            num /= common\n            denom /= common\n        }\n        return "\\(num)/\\(denom)"\n    }\n}\n\n```
['Math', 'String', 'Swift']