# python3 简单的算法题

### 求出1+2+3+..+100的和

```python
  print("计算1+2+3+...+100的结果：")
    result=0
    for i in range(101):
        result+=i
    print(result)
```

### 求出1-2+3-4+..+99 的结果

```python
num = 0
for i in range(100):
    if i % 2 == 1:
        num +=i
    else:
        num -+i
print(num)
```

### 求输入的三个数如何由大到小输出

```python
num = input('请输入数字\n')
num = num.split()
a,b,c = num
a,b,c = int(a),int(b),int(c)
if a > b : a,b = b,a
if a > c : a,c = c,a
if b > c : b,c = c,b
print("输出结果 ： %d %d %d" %(a,b,c))  # 也可以使用sort方法进行排序

s = [input(),input(),input()]
s.sort()
print "输出结果: %s" %s
```

### 输出99乘法口诀表

```python
for i in range(1,10):
        for j in range(1,10):
            print("%d*%d = %-3d" %(i,j,i*j),end="")
        print() 
        
# 另一种方法
c = 0
while c < 9:
    c +=1
    a = 0
    while a < c:
        a += 1
        print('{} x {} = {}'.format(c,a,a*c),end=" ")
    print()
```

### 输入n个数字，排列出有这n个数字组成的不同n位数

```python
s = (1, 2, 3, 4)
for a in s:
    for b in s:
        for c in s:
            if a != b and b != c and c != a:
                print("%d%d%d" % (a, b, c))
```