洛谷 P1147 连续自然数和

#include<iostream>
#include<cmath>
using namespace std;
typedef long long ll;
int main(){
    ll N;
    cin >> N;
    for(ll i = 1; i <= N / 2; i++){
        ll t = 2 * N + i * i - i;
        ll delt = 4 * t + 1;
        if(delt < 0) continue;
        else{
            ll x = (ll)(-1 + sqrt(delt)) / 2;
            if(x * x + x - t == 0 && i < x) cout << i << " " << x << endl;
        }
    }
    return 0;
}