P8251 [NOI Online 2022 提高组] 丹钓战（民间数据）

R72363649

Luogu/P8251/P8251.cpp

@@ -0,0 +1,87 @@
+#include <iostream>
+#include <stack>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 5e5 + 5;
+
+struct node {
+    int a, b, idx;
+
+    node()
+        : a(0), b(0), idx(0) {}
+    node(int _a, int _b, int _idx)
+        : a(_a), b(_b), idx(_idx) {}
+};
+
+int n, q, a[N], b[N], id[N], t[N], ans[N];
+std::stack<node> st;
+std::vector<int> aa[N], bb[N];
+std::pair<int, int> qq[N];
+
+int lowbit(int x) {
+    return x & (-x);
+}
+
+void add(int x) {
+    for (; x <= n; x += lowbit(x))
+        t[x]++;
+}
+
+int ask(int x) {
+    int ans = 0;
+    for (; x; x -= lowbit(x))
+        ans += t[x];
+    return ans;
+}
+
+inline int sum(int x, int y) {
+    return ask(y) - ask(x - 1);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n >> q;
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+    for (int i = 1; i <= n; i++) {
+        cin >> b[i];
+    }
+
+    st.push(node(-1, 0, 0));
+    for (int i = 1; i <= n; i++) {
+        while (!st.empty() && (st.top().a == a[i] || st.top().b <= b[i])) st.pop();
+        if (!st.empty()) id[i] = st.top().idx;
+        st.push(node(a[i], b[i], i));
+    }
+
+    for (int i = 1; i <= n; i++) {
+        aa[id[i]].push_back(i);
+    }
+    for (int i = 1; i <= q; i++) {
+        cin >> qq[i].first >> qq[i].second;
+        bb[qq[i].first].push_back(i);
+    }
+
+    for (int i = 1; i <= n; i++) {
+        for (int k = 0; k < aa[i - 1].size(); k++) {
+            add(aa[i - 1][k]);
+        }
+        for (int t : bb[i]) {
+            int l = qq[t].first,
+                r = qq[t].second;
+            ans[t] = sum(l, r);
+        }
+    }
+
+    for (int i = 1; i <= q; i++) {
+        cout << ans[i] << endl;
+    }
+
+    return 0;
+}