백준 1253: 좋다

https://www.acmicpc.net/problem/1253

1253번: 좋다

import sys
input = sys.stdin.readline
 
n = int(input())
a = list(map(int, input().split()))
a.sort()
count = 0
 
for k in range(n):
    find = a[k]
    i = 0
    j = n-1
 
    while i < j:
        sum = a[i] + a[j]
        if sum < find:
            i+=1
        elif sum > find:
            j-=1
        else:
            if i!=k and j!=k:
                count +=1
                break
            elif i==k:
                i+=1
            elif j==k:
                j-=1
 
print(count)