【每日一题】- 2021-08-11 - 两个质数和

[azl397985856]

Given an even number (greater than 2), return two prime numbers whose sum will be equal to the given number.

A solution will always exist. See Goldbach’s conjecture.

Example:

Input: 4
Output: 2 + 2 = 4
If there are more than one solution possible, return the lexicographically smaller solution.

If [a, b] is one solution with a <= b, and [c, d] is another solution with c <= d, then

[a, b] < [c, d]
If a < c OR a==c AND b < d.

[dalin-hub]

even=eval(input("please enter an even number\n"))
prime_list=[]
def isprime(i):
    for j in range(2,i-1):
        if i%j==0:
            return False
    return True
for i in range(2,even-1):
    if isprime(i):
        prime_list.append(i)
for i in prime_list:
    for j in prime_list:
        if i+j==even and i<=j:
            print("%d+%d=%d"%(i,j,even))

[stale]

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