func twoSum(nums:[Int],_ target:Int) -> Bool {
var set = Set<Int>()
for num in nums {
if set.contains(num) {
return true
}
set.insert(num)
}
return false
}
class Solution {
func firstUniqChar(_ s: String) -> Int {
var dic = [Character: Bool]()
for char in s {
if let _ = dic[char] {
dic[char] = true
}
else {
dic[char] = false
}
}
for (i,char) in Array(s).enumerated() {
if dic[char]! == false {
return i
}
}
return -1
}
}