codeforces 161 Div2 B

B. Squares

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Vasya has found a piece of paper with a coordinate system written on it. There are n distinct squares drawn in this coordinate system. Let's number the squares with integers from 1 to n. It turned out that points with coordinates (0, 0) and (a_i, a_i) are the opposite corners of the i-th square.

Vasya wants to find such integer point (with integer coordinates) of the plane, that belongs to exactly k drawn squares. We'll say that a point belongs to a square, if the point is located either inside the square, or on its boundary.

Help Vasya find a point that would meet the described limits.

Input

The first line contains two space-separated integers n, k (1 ≤ n, k ≤ 50). The second line contains space-separated integersa₁, a₂, ..., a_n (1 ≤ a_i ≤ 10⁹).

It is guaranteed that all given squares are distinct.

Output

In a single line print two space-separated integers x and y (0 ≤ x, y ≤ 10⁹) — the coordinates of the point that belongs to exactly ksquares. If there are multiple answers, you are allowed to print any of them.

If there is no answer, print "-1" (without the quotes).

Sample test(s)

input

4 3
5 1 3 4

output

2 1

input

3 1
2 4 1

output

4 0

input

4 50
5 1 10 2

output

-1

对ai排序后从大到小数 即可

附代码：

 1 #include
 2 #include
 3 
 4 int cmp(const void *a,const void *b)
 5 {
 6     return *(int *)b-*(int *)a;
 7 }
 8 
 9 int arr[50]={0};
10 
11 int main(void)
12 {
13     int n, k, number, status=0;
14     int i;
15     scanf("%d %d", &n, &k);
16     for( i=0; i)
17         scanf("%d", &arr[i]);
18 
19     qsort( arr, n, sizeof(int), cmp);
20     for( i=1; i<=k; i++)
21     {
22         if( i>n)
23         {
24             i=n;
25             status=1;
26             break;
27         }
28     }
29     i--;
30     if( status)
31         printf("-1\n");
32     else
33         printf("%d 0\n", arr[i-1]);
34 
35     return 0;
36 }

 

转载于:https://www.cnblogs.com/shadow-justice/archive/2013/01/17/2865460.html