Question

How to merge two strings based on shared suffix and prefix in Swift

Answer 1

import Foundation

func mergeOnOverlap(_ a: String, _ b: String) -> String {
    let lenA = a.count
    let lenB = b.count

    let maxPossibleOverlapLen = min(lenA, lenB)

    var overlap = 0

    for len in stride(from: maxPossibleOverlapLen, through: 1, by: -1) {
        let startA = a.index(a.endIndex, offsetBy: -len)
        let prefixB = b.prefix(len)

        if a[startA...] == prefixB {
            overlap = len
            break
        }
    }

    let dropIndex = b.index(b.startIndex, offsetBy: overlap)
    return a + b[dropIndex...]
}

let a = "fantasy time travel technology"
let b = "technology extraterrestrial life"

print(mergeOnOverlap(a, b))



/*
run:

fantasy time travel technology extraterrestrial life

*/

 

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