题目描述
You are given an array of N integers A[1] , A[2] , ... , A[N] . You have to answer Q queries. Each query consists of 3 integers L, R and K. For each query, you have to find the value of the Skipping Sum in the following manner :
def skipping_sum(L,R,K) :
sum = 0
while L ≤ R :
sum = sum + A[L]
L = L + K
return sum
Input
The first line consists of 2 space separated integers N and Q. The next line consists of N space separated integers, the i^th integer being A[i]. Then, Q lines follow, each line consisting of 3 space separated integers L, R and K.
Output
Print the answer to each query on a new line.
Constraints
1 ≤ N ≤ 10^5
1 ≤ Q ≤ 10^5
0 ≤ A[i] ≤ 10^5
1 ≤ L ≤ R ≤ N
1 ≤ K ≤ 10
NOTE:
We are using 1-based indexing for array A.
SAMPLE INPUT
8 6
5 4 2 1 7 9 10 9
1 8 1
1 8 2
4 8 9
3 7 2
3 7 3
3 7 4
SAMPLE OUTPUT
47
24
1
19
11
12
Explanation
For query 1 : A[1] + A[2] + A[3] + A[4] + A[5] + A[6] + A[8] = 47
For query 2 : A[1] + A[3] + A[5] + A[7] = 24
For query 3 : A[4] = 1
For query 4 : A[3] + A[5] + A[7] = 19
For query 5 : A[3] + A[6] = 11
For query 6 : A[3] + A[7] = 12
输入格式
见题面
输出格式
见题面