In a array A
of size 2N
, there are N+1
unique elements, and exactly one of these elements is repeated N times.
Return the element repeated N
times.
Example 1:
Input: [1,2,3,3]
Output: 3
Example 2:
Input: [2,1,2,5,3,2]
Output: 2
Example 3:
Input: [5,1,5,2,5,3,5,4]
Output: 5
Note:
4 <= A.length <= 10000
0 <= A[i] < 10000
A.length
is even
在大小为 2N
的数组 A
中有 N+1
个不同的元素,其中有一个元素重复了 N
次。
返回重复了 N
次的那个元素。
示例 1:
输入:[1,2,3,3] 输出:3
示例 2:
输入:[2,1,2,5,3,2] 输出:2
示例 3:
输入:[5,1,5,2,5,3,5,4] 输出:5
提示:
4 <= A.length <= 10000
0 <= A[i] < 10000
A.length
为偶数
280ms
1 class Solution { 2 func repeatedNTimes(_ A: [Int]) -> Int { 3 var set:Set<Int> = Set<Int>() 4 for x in A 5 { 6 if set.contains(x) 7 { 8 return x 9 } 10 set.insert(x) 11 } 12 return -1 13 } 14 }
300ms
1 class Solution { 2 func repeatedNTimes(_ A: [Int]) -> Int { 3 var n:Int = A.count 4 var f:[Int] = [Int](repeating:0,count:100000) 5 for v in A 6 { 7 f[v] += 1 8 } 9 10 for i in 0..<100000 11 { 12 if f[i] > 1 13 { 14 return i 15 } 16 } 17 return -1 18 } 19 }