Codeforces Round #332 (Div. 2) D. Spongebob and Squares（枚举）

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<vector>
 4 #include<cmath>
 5 using namespace std;
 6 
 7 typedef long long ll;
 8 typedef pair<ll,ll> pll;
 9 
10 ll x;
11 vector<pll> ans1,ans2;
12 
13 int main()
14 {
15     //freopen("in.txt","r",stdin);
16     ll tot = 0;
17     scanf("%lld",&x);
18     for(ll n=1;;n++)
19     {
20         ll a = n*(n+1) - n*(n+1)/2;
21         ll b = n*(n+1)*(2*n+1)/6 - n*n*(n+1)/2;
22         if(b > x)  break;
23         if((x  - b)%a == 0)
24         {
25             ll m = (x - b)/a;
26             if(m<n)  continue;
27             ans1.push_back(make_pair(n,m));
28             tot++;
29             if(m!=n)
30             {
31                 ans2.push_back(make_pair(m,n));
32                 tot++;
33             }
34         }
35     }
36     printf("%lld\n",tot);
37     for(int i=0;i<ans1.size();i++)
38     {
39         printf("%lld %lld\n",ans1[i].first,ans1[i].second);
40     }
41     for(int i=ans2.size()-1;i>=0;i--)
42     {
43         printf("%lld %lld\n",ans2[i].first,ans2[i].second);
44     }
45     return 0;
46 }