题解 | 【模板】静态区间和（前缀和）

n, c = map(int,input().split())
l = list(map(int,input().split()))
p = [0] * (n+1)
for i in range(n):
    p[i+1] = p[i] + l[i]
for i in range(c):
    a, d = map(int,input().split())
    s = p[d] - p[a-1]
    print(s)