Maximum prefix sum for a given range
Easy Accuracy: 25.23% Submissions: 1083 Points: 2

Given an array of n integers and q queries, each query having a range from l to r. Find the maximum prefix-sum for the range l to r.
NOTE: Assume indexing from 0.

Input: a[] = {-1, 2, 3, -5}
q = 2
l = 0, r = 3
l = 1, r = 3

Output: 4
5

Explanation:- The range (0, 3) in the 1st query has
[-1, 2, 3, -5], since it is prefix,
we have to start from -1. Hence, the
max prefix sum will be -1 + 2 + 3 = 4.
The range (1, 3) in the 1st query has
[2, 3, -5], since it is prefix, we
have to start from 2. Hence, the max
prefix sum will be 2 + 3 = 5.


Input:
The first line consists of an integer T i.e number of test cases. The first line of each test case consists of two integers n and q.Then next line consists of n spaced integers. The last line of each test case consists of q pairs of integers representing l and r.

Output:

Constraints:
1<=T<=100
1<=n,q,a[i]<=104

Example:
Input:

2
4 2
-1 2 3 -5
0 3 1 3
8 1
-2 -3 4 -1 -2 1 5 -3
1 7

Output:
4 5
4