A ← 整数の列 # 1 から開始
AC[0] ← 0

    
for i ← 1 to N-1:
    AC[i] ← AC[i-1] + A[i]

Q ← [l, r] 形式の質問の列

for q in Q:
    l ← q.l
    r ← q.r
    sum ← AC[r] - AC[l-1]