Street Numbers POJ - 1320  [佩尔方程]

题意: 求方程 (2x+1)^2-8*y^2=1 的前10个正整数解

思路:佩尔方程的应用

#include<cstdio>
#include<vector>
#include<cmath>
#include<math.h>
#include<string>
#include<string.h>
#include<iostream>
#include<algorithm>
#include<map>
#define PI acos(-1.0)
#define pb push_back
#define F first
#define S second
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int N=1005;
const int MOD=1e9+7;
const double EPS=1e-10;
ll n,k;

vector<pair<ll,ll> > ans;
int main(void){
    ll y0=0,y1=1,x0=3;
    while((int)ans.size()<10){
        ll y2=2*x0*y1-y0;
        ll x= 1+8*y2*y2;
        x=(sqrt(x)-1)/2;
        if(y2<x) ans.pb({y2,x});
        y0=y1,y1=y2;
    }
    for(int i=0;i<10;i++)
        printf("%10lld%10lld\n",ans[i].first,ans[i].second);
}