4 seconds
256 megabytes
standard input
standard output
Bob has a favorite number k and ai of length n. Now he asks you to answer m queries. Each query is given by a pair li and ri and asks you to count the number of pairs of integers i and j, such that l ≤ i ≤ j ≤ r and the xor of the numbers ai, ai + 1, ..., aj is equal to k.
The first line of the input contains integers n, m and k (1 ≤ n, m ≤ 100 000, 0 ≤ k ≤ 1 000 000) — the length of the array, the number of queries and Bob's favorite number respectively.
The second line contains n integers ai (0 ≤ ai ≤ 1 000 000) — Bob's array.
Then m lines follow. The i-th line contains integers li and ri (1 ≤ li ≤ ri ≤ n) — the parameters of the i-th query.
Print m lines, answer the queries in the order they appear in the input.
6 2 3
1 2 1 1 0 3
1 6
3 5
7
0
5 3 1
1 1 1 1 1
1 5
2 4
1 3
9
4
4
In the first sample the suitable pairs of i and j for the first query are: (1, 2), (1, 4), (1, 5), (2, 3), (3, 6), (5, 6), (6, 6). Not a single of these pairs is suitable for the second query.
In the second sample xor equals 1 for all subarrays of an odd length.
题意:给你一个大小为n的序列,然后给你一个数字k,再给出m组询问
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#define X first
#define Y second
#define clr(u,v); memset(u,v,sizeof(u));
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn=<<;
const int INF=0x3f3f3f3f;
ll pos[maxn];
ll flag[maxn],ans[maxn];
int a[maxn];
struct node
{
int l,r,id;
}Q[maxn];
bool cmp(node a,node b)
{
if (pos[a.l]==pos[b.l])
{
return a.r<b.r;
}
return pos[a.l]<pos[b.l];
}
int n,m,k;
int L=,R=;
ll Ans=;
void add(int x)
{
Ans+=flag[a[x]^k];
flag[a[x]]++;
}
void del(int x)
{
flag[a[x]]--;
Ans-=flag[a[x]^k];
}
int main()
{
scanf("%d%d%d",&n,&m,&k);
int sz=sqrt(n);
for (int i=;i<=n;i++)
{
scanf("%d",&a[i]);
a[i]^=a[i-];
pos[i]=i/sz;
}
for (int i=;i<=m;i++)
{
scanf("%d%d",&Q[i].l,&Q[i].r);
Q[i].id=i;
}
flag[]=;
sort(Q+,Q+m+,cmp);
for (int i=;i<=m;i++)
{
while (L<Q[i].l)
{
del(L-);
L++;
}
while (L>Q[i].l)
{
L--;
add(L-);
}
while (R<Q[i].r)
{
R++;
add(R);
}
while (R>Q[i].r)
{
del(R);
R--;
}
ans[Q[i].id]=Ans;
}
for (int i=;i<=m;i++)
printf("%I64d\n",ans[i]);
return ;
}
2016-09-25 03:31:38