func findMostCommonPair(in s: String) -> (pair: String, count: Int)? {
var pairFrequency: [String: Int] = [:]
// Iterate through the string to get pairs of characters
for i in 0..<(s.count - 1) {
let startIndex = s.index(s.startIndex, offsetBy: i)
let endIndex = s.index(startIndex, offsetBy: 1)
let pair = String(s[startIndex...endIndex])
// Update the frequency dictionary
pairFrequency[pair, default: 0] += 1
}
// Find the most common pair
if let (mostCommonPair, count) = pairFrequency.max(by: { $0.value < $1.value }) {
return (mostCommonPair, count)
}
return nil
}
let s = "xzvxdeshaalzxzmdenlopxzxzxzaaqdewrzaaaapeerxzxz";
if let result = findMostCommonPair(in: s) {
print("Most common pair: \(result.pair) with count: \(result.count)")
} else {
print("No pairs found.")
}
/*
run:
Most common pair: xz with count: 7
*/
