1399C Boats Competition.cpp

/*
    author    : MishkatIT
    created   : Wednesday 2024-02-21-23.50.44
*/

#include<bits/stdc++.h>
#define fio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define debug(_) cout << #_ << " is " << _ << '\n';

using namespace std;
using ll        = long long;
using ld        = long double;
const ll mod    = 1e9 + 7;
const ll N      = 2e5 + 10;
const ll inf    = 1e9;
const ll linf   = 1e18;

int main()
{
    fio;
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        vector<int> v(n);
        for (auto& i : v) {
            cin >> i;
        }
        sort(v.begin(), v.end());
        int mx = 0;
        for (int s = 100; s > 0; s--) {
            int l = 0, r = n - 1;
            int cnt = 0;
            while(l < r) {
                if (v[l] + v[r] == s) {
                    cnt++;
                    l++, r--;
                    mx = max(mx, cnt);
                } else if (v[l] + v[r] < s) {
                    l++;
                } else {
                    r--;
                }
            }
        }
        cout << mx << '\n';
    }
    return 0;
}