#1709. 【2022.10.31 联考】出题（questions）

https://sjzezoj.com/submission/62647

S2OJ/1709/1709.cpp

@@ -0,0 +1,71 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <tuple>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+int n, q, t, a[N], cnt[N], cnt2[N], ans[N];
+std::tuple<int, int, int, int> queries[N];
+
+void add(int x) {
+    cnt2[++cnt[x]]++;
+}
+
+void del(int x) {
+    cnt2[cnt[x]--]--;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    cin >> q;
+
+    for (int i = 1; i <= q; i++) {
+        cin >> std::get<1>(queries[i]) >> std::get<2>(queries[i]) >> std::get<3>(queries[i]);
+        std::get<0>(queries[i]) = i;
+    }
+
+    t = std::sqrt(q);
+    std::sort(queries + 1, queries + 1 + q, [&](auto a, auto b) -> bool {
+        int p = std::get<1>(a) / t,
+            q = std::get<1>(b) / t;
+
+        return p == q
+                 ? (p & 1)
+                     ? std::get<2>(a) < std::get<2>(b)
+                     : std::get<2>(a) > std::get<2>(b)
+                 : p < q;
+    });
+
+    cnt2[0] = n;
+    for (int _ = 1, i = 0, j = 1; _ <= q; _++) {
+        int id, l, r, k;
+
+        std::tie(id, l, r, k) = queries[_];
+
+        while (i < r) add(a[++i]);
+        while (i > r) del(a[i--]);
+        while (j > l) add(a[--j]);
+        while (j < l) del(a[j++]);
+
+        ans[id] = cnt2[k];
+    }
+
+    for (int i = 1; i <= q; i++) {
+        cout << ans[i] << endl;
+    }
+
+    return 0;
+}