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https://git.sb/baoshuo/OI-codes.git
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74 lines
1.3 KiB
C++
74 lines
1.3 KiB
C++
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#include <iostream>
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#include <algorithm>
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#include <cmath>
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#include <tuple>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 50005,
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M = 200005,
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S = 1e6 + 5;
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int n, m, a[N], c[S], t, ans[M];
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std::vector<std::tuple<int, int, int>> q;
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inline int get(int x) {
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return x / t;
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}
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inline void add(int x, int& r) {
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if (!c[x]++) r++;
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}
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inline void del(int x, int& r) {
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if (!--c[x]) r--;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> n;
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for (int i = 1; i <= n; i++) {
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cin >> a[i];
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}
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t = sqrt(n);
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cin >> m;
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for (int i = 1, l, r; i <= m; i++) {
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cin >> l >> r;
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q.push_back(std::make_tuple(i, l, r));
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}
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std::sort(q.begin(), q.end(), [&](auto a, auto b) {
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int p = get(std::get<1>(a)),
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q = get(std::get<1>(b));
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return p == q ? std::get<2>(a) < std::get<2>(b) : p < q;
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});
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for (int k = 0, i = 0, j = 1, res = 0, id, l, r; k < q.size(); k++) {
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std::tie(id, l, r) = q[k];
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while (i < r) add(a[++i], res);
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while (i > r) del(a[i--], res);
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while (j < l) del(a[j++], res);
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while (j > l) add(a[--j], res);
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ans[id] = res;
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}
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for (int i = 1; i <= m; i++) {
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cout << ans[i] << endl;
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}
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return 0;
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}
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