---
tags: csc
---

{%hackmd theme-dark %}

Computer Science Club (3)
===

Note
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[[PYTHON] LIST 篇](https://happylearningcoding.blogspot.com/2020/07/python-list.html)

List Usage
---

### dandanjudge
[a004: 經濟大恐荒](http://dandanjudge.fdhs.tyc.edu.tw/ShowProblem?problemid=a004)

題意 : `ans = sum(a[i] * (i + 1))`

n = int(input())
lst = [int(x) for x in input().split()]
res = 0

for i in range(n):
    res += lst[i] * (i + 1)

print(res)

[a164. 0927進階班作業-區間和](http://dandanjudge.fdhs.tyc.edu.tw/ShowProblem?problemid=a164)

`data`
| 0 | 1 | 2 | 3 | 4 | 5 |
| - | - | - | - | - | - |
`accumulate`
| 0 | 1 | 3 | 6 | 10 | 15 |
| - | - | - | - | - | - |

區間和 $=$ `accumulate[r]` $-$ `accumuate[l - 1]`

`code`

lst = [0] + [int(x) for x in input().split()] # data
for i in range(1, len(lst)):
    lst[i] += lst[i - 1] # accumulate

n = int(input())

for _ in range(n):
    l, r = [int(x) for x in input().split()]
    if l > r:
        l, r = r, l
    print(lst[r] - lst[l - 1])