# [CF703D]Mishka and Interesting sum/[BZOJ5476]位运算

## 源代码：

#include<map>
#include<cstdio>
#include<cctype>
#include<algorithm>
inline int getint() {
register char ch;
while(!isdigit(ch=getchar()));
register int x=ch^'0';
while(isdigit(ch=getchar())) x=(((x<<2)+x)<<1)+(ch^'0');
return x;
}
const int N=1e6+1,M=1e6;
int n,a[N];
struct Query {
int l,r,id;
bool operator < (const Query &rhs) const {
return r<rhs.r;
}
};
Query q[M];
class FenwickTree {
private:
int val[N];
int lowbit(const int &x) const {
return x&-x;
}
public:
void modify(int p,const int &x) {
for(;p<=n;p+=lowbit(p)) {
val[p]^=x;
}
}
int query(int p) const {
int ret=0;
for(;p;p-=lowbit(p)) {
ret^=val[p];
}
return ret;
}
int query(const int &l,const int &r) const {
return query(r)^query(l-1);
}
};
FenwickTree t;
std::map<int,int> last_pos;
int ans[M];
int main() {
n=getint();
for(register int i=1;i<=n;i++) {
a[i]=getint();
}
const int m=getint();
for(register int i=0;i<m;i++) {
q[i].l=getint();
q[i].r=getint();
q[i].id=i;
}
std::sort(&q[0],&q[m]);
for(register int i=1,j=0;i<=n;i++) {
if(last_pos[a[i]]) {
t.modify(last_pos[a[i]],a[i]);
}
for(;j<m&&q[j].r==i;j++) {
ans[q[j].id]=t.query(q[j].l,q[j].r);
}
last_pos[a[i]]=i;
}
for(register int i=0;i<m;i++) {
printf("%d\n",ans[i]);
}
return 0;
}
posted @ 2019-02-12 19:11 skylee03 阅读(...) 评论(...) 编辑 收藏