codeforces #384 Vladik and fractions （构造算法）

Problem:
给定一个n，有三个不超过10^9的x,y,z，使得2/n = 1/x + 1/y + 1/z，后三个数是真分数。
Solution:
将已知数2/n进行分解，n/2 = 1/n + 1/(n+1) + 1/(n*(n+1));

#include<cstdio>#include<iostream>#include<sstream>#include<cstdlib>#include<cmath>#include<cctype>#include<string>#include<cstring>#include<algorithm>#include<stack>#include<queue>#include<set>#include<map>#include<ctime>#include<vector>#include<fstream>#include<list>using namespace std;#define ms(s) memset(s,0,sizeof(s))const double PI = 3.141592653589;const int INF = 0x3fffffff;int main(){    //    freopen("/Users/really/Documents/code/input","r",stdin);    //    freopen("/Users/really/Documents/code/output","w",stdout);    ios::sync_with_stdio(false);    long long n;    cin >> n;    if(n == 1LL || n*(n+1) > 1000000000LL)        cout << "-1" << endl;    else{        cout << n << " " << (n+1) << " " << n*(n+1) << endl;    }    return 0;}