Codeforces 617 E. XOR and Favorite Number

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<vector>
 5 #include<cstdlib>
 6 #include<cmath>
 7 #include<cstring>
 8 using namespace std;
 9 #define maxn 3001000
10 #define llg long long 
11 #define yyj(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);
12 llg n,m,a[maxn],ans,L,R,Ans[maxn],c[maxn],SIZE,k,qzxor[maxn];
13 struct node
14 {
15     llg l,r,num;
16 }ask[maxn];
17 
18 inline int getint()
19 {
20        int w=0,q=0; char c=getchar();
21        while((c<‘0‘ || c>‘9‘) && c!=‘-‘) c=getchar(); if(c==‘-‘) q=1,c=getchar(); 
22        while (c>=‘0‘ && c<=‘9‘) w=w*10+c-‘0‘, c=getchar(); return q ? -w : w;
23 }
24 
25 bool cmp(const node&a,const node&b)
26 {
27     if (a.l/SIZE==b.l/SIZE) return a.r<b.r;
28     return a.l/SIZE<b.l/SIZE;
29 }
30 
31 void inc(llg x,llg val) {if (x==0 || x>n) return ;ans+=c[val^k],c[val]++;}
32 void dec(llg x,llg val) {if (x==0 || x>n) return ; c[val]--; ans-=c[val^k];}
33 
34 int main()
35 {
36     yyj("xor");
37     cin>>n>>m>>k;
38     for (llg i=1;i<=n;i++) a[i]=getint(),qzxor[i]=qzxor[i-1]^a[i];
39     for (llg i=1;i<=m;i++) ask[i].l=getint(),ask[i].r=getint(),ask[i].num=i;
40     SIZE=sqrt(n);
41     sort(ask+1,ask+m+1,cmp);
42     c[0]=1;
43     for (llg i=1;i<=m;i++)
44     {
45         llg l=ask[i].l,r=ask[i].r;
46         if (L>l) for (llg i=L-1;i>=l;i--) inc(i,qzxor[i-1]);
47         if (r>R) for (llg i=R+1;i<=r;i++) inc(i,qzxor[i]);
48         if (L<l)  for (llg i=L;i<l;i++) dec(i,qzxor[i-1]);
49         if (r<R) for (llg i=R;i>r;i--) dec(i,qzxor[i]);
50         Ans[ask[i].num]=ans;
51         L=l,R=r;
52     }
53     for (llg i=1;i<=m;i++) printf("%lld ",Ans[i]);
54     return 0;
55 }