# 作业帮

## 笔试-作业帮-180925

* 单选 5，填空 5，编程 2，问答 2
* 编程不允许跳出页面

### Index

* [1. 点对距离](#1-点对距离)
* [2. 扩展型表达式求值](#2-扩展型表达式求值)

### 1. 点对距离

**Python**（60%）

* 试了各种情况，不知道哪里有问题

  \`\`\`python

  from math import ceil, floor

def foo(ax, ay, bx, by): d = ((ax - bx)**2 + (ay - by)**&#x32;)\*\*0.5

```
#return round(d, 5)
return d
```

k = int(input()) n = int(input())

P = \[] for \_ in range(n): x, y = list(map(float, input().split())) P.append(\[x, y])

D = \[] for i in range(n): for j in range(i+1, n): d = foo(P\[i]\[0], P\[i]\[1], P\[j]\[0], P\[j]\[1]) D.append(d)

D.sort()

## print(D)

N = len(D) - 1

## print(N)

## print(ceil(N \* (k / 100)))

ans = D\[ceil(N \* (k / 100))]

## print("%0.5f" % ans)

print(round(ans, 5))

## print(ans)

````
## 2. 扩展型表达式求值

<div align="center"><img src="../_assets/TIM截图20180925203442.png" height="" /></div>
<div align="center"><img src="../_assets/TIM截图20180925203454.png" height="" /></div>
<div align="center"><img src="../_assets/TIM截图20180925203504.png" height="" /></div>

**Python**（57.14%）
- 不能跳出页面，实在不想写这种题，偷鸡过了 57%
```python
def bar(s):
    while "%" in s:
        i = s.find("%")
        j = i - 1
        while s[j].isdigit():
            j -= 1

        s = s[:j+1] + str(int(s[j+1: i]) / 100) + s[i+1:]
    return s

def foo(s):
    if "**" in s or "++" in s or "--" in s:
        return "error"

    s = bar(s)

    try:
        ans = eval(s)
        if isinstance(ans, int):
            return "%d" % ans
        else:
            return "%0.3f" % ans
            #return round(ans, 3)
    except e:
        return "error"

s = input()
ans = foo(s)
#print(bar(s))
print(ans)
````
