#1558. 【2022.9.14 联考】3aab198230b8fd9f

https://sjzezoj.com/submission/56419

S2OJ/1558/1558.cpp

@@ -0,0 +1,39 @@
+#include <iostream>
+#include <unordered_map>
+#include <unordered_set>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e6 + 5;
+
+int n, m, a[N];
+long long ans;
+std::unordered_set<int> set;
+std::unordered_map<int, int> map;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    for (int i = 1, j = 0; i <= n - m + 1; i++) {
+        while (j < n && set.size() < m) {
+            set.insert(a[++j]);
+            map[a[j]]++;
+        }
+
+        if (set.size() == m) ans += n - j + 1;
+        if (!--map[a[i]]) set.erase(a[i]);
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}