• API
• FAQ
• Tools
• Archive
SHARE
TWEET

# Untitled

a guest Jan 17th, 2019 57 Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
1. A zero-indexed array A consisting of N integers is given. An equilibrium index of this array is any integer P such that 0 ≤ P < N and the sum of elements of lower indices is equal to the sum of elements of higher indices, i.e.
2. A[0] + A[1] + ... + A[P−1] = A[P+1] + ... + A[N−2] + A[N−1].
3. Sum of zero elements is assumed to be equal to 0. This can happen if P = 0 or if P = N−1.
4.
5. For example, consider the following array A consisting of N = 7 elements:
6.
7. A[0] = -7   A[1] =  1   A[2] = 5
8. A[3] =  2   A[4] = -4   A[5] = 3
9. A[6] =  0
10. P = 3 is an equilibrium index of this array, because:
11.
12. A[0] + A[1] + A[2] = A[4] + A[5] + A[6]
13. P = 6 is also an equilibrium index, because:
14.
15. A[0] + A[1] + A[2] + A[3] + A[4] + A[5] = 0
16. and there are no elements with indices greater than 6.
17.
18. P = 7 is not an equilibrium index, because it does not fulfill the condition 0 ≤ P < N.
19.
20. Write a function
21.
22. class Solution { public int equi(int[] A); }
23.
24. that, given a zero-indexed array A consisting of N integers, returns any of its equilibrium indices. The function should return −1 if no equilibrium index exists.
25.
26. Assume that:
27.
28. N is an integer within the range [0..10,000,000];
29. each element of array A is an integer within the range [−2,147,483,648..2,147,483,647].
30. For example, given array A such that
31.
32. A[0] = -7   A[1] =  1   A[2] = 5
33. A[3] =  2   A[4] = -4   A[5] = 3
34. A[6] =  0
35. the function may return 3 or 6, as explained above.
36.
37. Complexity:
38.
39. expected worst-case time complexity is O(N);
40. expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).
41. Elements of input arrays can be modified.
RAW Paste Data
We use cookies for various purposes including analytics. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy.

Top