莫队
还是一道模板。。不过洛谷数据加强了,必须要奇偶性排序+吸氧才能过,BZOJ可以直接过的~
#include <bits/stdc++.h>
#define INF 0x3f3f3f3f
#define full(a, b) memset(a, b, sizeof a)
using namespace std;
typedef long long ll;
inline int lowbit(int x){ return x & (-x); }
inline int read(){
int X = 0, w = 0; char ch = 0;
while(!isdigit(ch)) { w |= ch == '-'; ch = getchar(); }
while(isdigit(ch)) X = (X << 3) + (X << 1) + (ch ^ 48), ch = getchar();
return w ? -X : X;
}
inline int gcd(int a, int b){ return b ? gcd(b, a % b) : a; }
inline int lcm(int a, int b){ return a / gcd(a, b) * b; }
template<typename T>
inline T max(T x, T y, T z){ return max(max(x, y), z); }
template<typename T>
inline T min(T x, T y, T z){ return min(min(x, y), z); }
template<typename A, typename B, typename C>
inline A fpow(A x, B p, C lyd){
A ans = 1;
for(; p; p >>= 1, x = 1LL * x * x % lyd)if(p & 1)ans = 1LL * x * ans % lyd;
return ans;
}
const int N = 500005;
const int M = 1000005;
int n, m, t, a[N], freq[M], ans, res[N];
struct Query{
int l, r, id, block;
bool operator < (const Query &rhs) const {
return (block ^ rhs.block) ? l < rhs.l : (block & 1) ? r < rhs.r : r > rhs.r;
}
}query[N];
inline void add(int k){
freq[a[k]] ++;
if(freq[a[k]] == 1) ans ++;
}
inline void remove(int k){
freq[a[k]] --;
if(freq[a[k]] == 0) ans --;
}
int main(){
n = read();
for(int i = 1; i <= n; i ++) a[i] = read();
m = read();
t = (int)sqrt(n);
for(int i = 1; i <= m; i ++){
query[i].l = read(), query[i].r = read();
query[i].id = i, query[i].block = (query[i].l - 1) / t + 1;
}
sort(query + 1, query + m + 1);
int l = 1, r = 0;
for(int i = 1; i <= m; i ++){
int curL = query[i].l, curR = query[i].r;
while(l < curL) remove(l ++);
while(l > curL) add(-- l);
while(r < curR) add(++ r);
while(r > curR) remove(r --);
res[query[i].id] = ans;
}
for(int i = 1; i <= m; i ++){
printf("%d
", res[i]);
}
return 0;
}