[Solution] Triple solution codeforces

Triple solution codeforces – Given an array 𝑎a of 𝑛n elements, print any value that appears at least three times or print -1 if there is no such value.

[Solution] Triple solution codeforces

The first line contains an integer 𝑡t (1𝑡1041≤t≤104) — the number of test cases.

The first line of each test case contains an integer 𝑛n (1𝑛21051≤n≤2⋅105) — the length of the array.

The second line of each test case contains 𝑛n integers 𝑎1,𝑎2,,𝑎𝑛a1,a2,…,an (1𝑎𝑖𝑛1≤ai≤n) — the elements of the array.

It is guaranteed that the sum of 𝑛n over all test cases does not exceed 21052⋅105.

Output

For each test case, print any value that appears at least three times or print -1 if there is no such value.

[Solution] Triple solution codeforces

Example
input

Copy
7
1
1
3
2 2 2
7
2 2 3 3 4 2 2
8
1 4 3 4 3 2 4 1
9
1 1 1 2 2 2 3 3 3
5
1 5 2 4 3
4
4 4 4 4
output

Copy
-1
2
2
4
3
-1
4

Triple solution codeforces

In the first test case there is just a single element, so it can’t occur at least three times and the answer is -1.

In the second test case, all three elements of the array are equal to 22, so 22 occurs three times, and so the answer is 22.

For the third test case, 22 occurs four times, so the answer is 22.

For the fourth test case, 44 occurs three times, so the answer is 44.

For the fifth test case, 1122 and 33 all occur at least three times, so they are all valid outputs.

For the sixth test case, all elements are distinct, so none of them occurs at least three times and the answer is -1.

For Solution

Click here

Leave a Comment