Getting started messing around bitset simple question

Links: https://ac.nowcoder.com/acm/contest/132/C?&headNav=www
Source: Cattle-off network

Simple messing around title

Time limit: C / C ++ 1 second, 2 seconds languages other
space restrictions: C / C ++ 32768K, other languages 65536k
64bit the IO the Format: LLD%

Title Description

There are a number n, is the i-th X _i 

X _I  can take [L _I , R & lt _I ] in an arbitrary value.

Set $\mathrm{S\; =\; [Sigma\; X\; I\; 2\; S\; =\; \Sigma xi2,\; find\; the\; number\; of\; species\; S.}$

Specific ideas:

bitset

00011 bitset represents the first such number exists, the second number is present (not binary).

Then every once in a calculation on the basis of adding just fine.

 1 #include<bits/stdc++.h>
 2 #include<bitset>
 3 using namespace std;
 4 # define ll long long
 5 # define LL_inf (1ll<<60)
 6 # define inf 0x3f3f3f3f3
 7 const int maxn = 1e6+20;
 8 const int mod = 1e9+7;
 9 bitset<maxn>ans;
10 bitset<maxn>tmp;
11 int main()
12 {
13     int n;
14     scanf("%d",&n);
15     int st,ed;
16     ans[0]=1;
17     for(int i=1; i<=n; i++)
18     {
19         scanf("%d %d",&st,&ed);
20         tmp.reset();
21         for(int j=st; j<=ed; j++)
22         {
23             tmp|=ans<<j*j;
24         }
25         ans=tmp;
26     }
27     cout<<ans.count()<<endl;
28     return 0;
29 }