2551: Arrays
Description
You are given two arrays A and B consisting of integers, sorted in non-decreasing order. Check whether it is possible to choose k numbers in array A and choose m numbers in array B so that any number chosen in the first array is strictly less than any number chosen in the second array.
The first line contains two integers nA,nB (1≤nA,nB≤105), separated by a space − the sizes of arrays A and B, correspondingly.
The second line contains two integers k and m (1≤k≤nA,1≤m≤nB), separated by a space.
The third line contains nA numbers a1,a2,... anA (-109≤a1≤a2≤...≤anA≤109), separated by spaces − elements of array A.
The fourth line contains nB integers b1,b2,... bnB (-109≤b1≤b2≤...≤bnB≤109), separated by spaces − elements of array B.
Print "YES" (without the quotes), if you can choose k numbers in array A and m numbers in array B so that any number chosen in array A was strictly less than any number chosen in array B. Otherwise, print "NO" (without the quotes).
3 3
2 1
1 2 3
3 4 5
YES
3 3
3 3
1 2 3
3 4 5
NO
5 2
3 1
1 1 1 1 1
2 2
YES
In the first sample test you can, for example, choose numbers 1 and 2 from array A and number 3 from array B (1 < 3 and 2 < 3).
In the second sample test the only way to choose k elements in the first array and m elements in the second one is to choose all numbers in both arrays, but then not all the numbers chosen in A will be less than all the numbers chosen in B: 
.