[punch in - Blue Bridge Cup] day 1 --% 7F format output

subject 1

Based on practice A+B problem
The first line of input contains two integers , Separated by spaces , respectively A、B.
Output one line , Include an integer , Express A+B Value .

Ideas

Use... After input split Division

Code

a, b = map(int, input().split())
print(a+b)

subject 2

Based on practice Fibonacci The sequence
Fibonacci The recurrence formula of sequence is ：Fn=Fn-1+Fn-2, among F1=F2=1.
When n The larger the ,Fn It's also very large. , Now we want to know ,Fn Divide 10007 What is the remainder of .
Input contains an integer n.
Output one line , Contains an integer , Express Fn Divide 10007 The remainder of .

Ideas

With iteration seek Fn after , Remainder

The test case has reached 999999 了 , Even the Fibonacci sequence stored in array can not reach the time and space specified in the topic , and fib(n) Will be very long ,long long int It can not meet the accuracy requirements , So we must change our thinking .
Because our answer is the most important remainder 10007, This number is less than 10007 when , That's the number . If it is greater than 10007, We can take the balance directly 10007, It has no effect on the final result .
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Code

f1=f2=1
fn=0
n = int(input())
if n == 1 or n == 2:
    print(1)
elif n > 2:
    for i in range(3, n+1):
        fn = (f1 + f2) % 10007
        f1 = f2
        f2 = fn
    print(fn)

subject 3

Based on practice Area of circle
Radius of given circle r, Find the area of a circle .
Input contains an integer r, Represents the radius of a circle .
Output one line , Contains a real number , Round to decimal 7 position , Represents the area of a circle .

Their thinking

The formula Π r^2, Note the output format

Code

PI=3.14159265358979323
r = int(input())
area = PI*r*r
print('%.7f' % area)

subject 4

Based on practice Sum a sequence
seek 1+2+3+…+n Value .
Input includes an integer n.
Output one line , Include an integer , Express 1+2+3+…+n Value .

Their thinking

The mathematical formula ：(n+1)*n/2

Code

n = int(input())
sum = n*(1+n)/2
print(int(sum))