44 lines
851 B
Python
44 lines
851 B
Python
import sys
|
|
|
|
n,k=map(int,sys.stdin.readline().rstrip().split())
|
|
oarr=list(map(int,sys.stdin.readline().rstrip().split()))
|
|
karr=[]
|
|
|
|
def merge_sort(l,r):
|
|
if l<r:
|
|
q=int((l+r)/2)
|
|
merge_sort(l,q)
|
|
merge_sort(q+1,r)
|
|
merge(l,q,r)
|
|
|
|
def merge(l,q,r):
|
|
tarr=[]
|
|
i=l
|
|
j=q+1
|
|
|
|
while i<=q and j<=r:
|
|
if oarr[i]<oarr[j]:
|
|
tarr.append(oarr[i])
|
|
karr.append(oarr[i])
|
|
i+=1
|
|
else:
|
|
tarr.append(oarr[j])
|
|
karr.append(oarr[j])
|
|
j+=1
|
|
while i<=q:
|
|
tarr.append(oarr[i])
|
|
karr.append(oarr[i])
|
|
i+=1
|
|
while j<=r:
|
|
tarr.append(oarr[j])
|
|
karr.append(oarr[j])
|
|
j+=1
|
|
|
|
for t in range(len(tarr)):
|
|
oarr[t+l]=tarr[t]
|
|
|
|
merge_sort(0,n-1)
|
|
if len(karr)<k:
|
|
print(-1)
|
|
else:
|
|
print(karr[k-1]) |