백준 소스코드 [C++] 1253 좋다

www.acmicpc.net/problem/1253

1253번: 좋다

백준 소스코드 [C++] 1253 좋다

#include <iostream>
#include <algorithm>
#include <queue>
#include <string.h>
#include <limits.h>
#include <vector>
#include <math.h>
#include <stack>
#include <bitset>
#include <string>
#include <set>
#include <map>
#include <unordered_map>
#include <sstream>
#define all(v) v.begin(), v.end()
#define pii pair<int,int>
#define make_unique(v) v.erase(unique(v.begin(), v.end()), v.end())
typedef long long ll;
using namespace std;

int arr[2001], n, res = 0;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

    cin >> n;
    for (int i = 0;i < n;i++) cin >> arr[i];
    sort(arr, arr + n);

    for (int i = 0;i < n;i++) {
        int L = 0, R = n - 1;
        while (L < R) {
            if (L == i) L++;
            else if (R == i) R--;
            else if (arr[L] + arr[R] == arr[i]){
                res++;
                break;
            }
            else if (arr[L] + arr[R] < arr[i]) L++;
            else R--;
        }
    }
    cout << res;

	return 0;
}