#2279. 「SCOI2007」降雨量

https://loj.ac/s/1306934

LibreOJ/2279/2279.cpp

@@ -0,0 +1,109 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+struct node {
+    int l, r, max;
+
+    node()
+        : l(0), r(0), max(0) {}
+    node(int _l, int _r)
+        : l(_l), r(_r), max(0) {}
+} tr[50005 << 2];
+
+int n, m, x, y, a[50005];
+map<int, int> m1;
+
+void pushup(int u) {
+    tr[u].max = max(tr[u << 1].max, tr[u << 1 | 1].max);
+}
+
+void build(int u, int l, int r) {
+    tr[u] = node(l, r);
+    if (l == r) {
+        tr[u].max = a[l];
+        return;
+    }
+    int mid = l + r >> 1;
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+    pushup(u);
+}
+
+int query(int u, int l, int r) {
+    if (l <= tr[u].l && tr[u].r <= r) {
+        return tr[u].max;
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    int s = 0;
+    if (l <= mid) s = max(s, query(u << 1, l, r));
+    if (r > mid) s = max(s, query(u << 1 | 1, l, r));
+    return s;
+}
+
+const char* solve(int x, int y) {
+    if (x == y) {
+        return "true";
+    } else if (x > y) {
+        return "false";
+    }
+    auto p1 = m1.lower_bound(x);
+    auto p2 = m1.lower_bound(y);
+    if (p2 == m1.end() || p2->first != y) {
+        if (p1 == m1.end() || p1->first != x) {
+            return "maybe";
+        }
+        --p2;
+        if (p1->second + 1 > p2->second || query(1, p1->second + 1, p2->second) < a[p1->second]) {
+            return "maybe";
+        } else {
+            return "false";
+        }
+    }
+    if (p1 == m1.end()) {
+        return "maybe";
+    }
+    if (p1->first == x) {
+        if (a[p1->second] < a[p2->second]) {
+            return "false";
+        }
+        if (p1->second + 1 > p2->second - 1) {
+            return y - x == p2->second - p1->second ? "true" : "maybe";
+        } else {
+            int mx = query(1, p1->second + 1, p2->second - 1);
+            if (mx >= a[p2->second]) {
+                return "false";
+            } else {
+                return y - x == p2->second - p1->second ? "true" : "maybe";
+            }
+        }
+    } else {
+        if (p1 == p2) {
+            return "maybe";
+        } else {
+            int mx = query(1, p1->second, p2->second - 1);
+            if (mx >= a[p2->second]) {
+                return "false";
+            } else {
+                return "maybe";
+            }
+        }
+    }
+    return "failed";
+}
+
+int main() {
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        cin >> x >> y;
+        m1[x] = i;
+        a[i] = y;
+    }
+    build(1, 1, n);
+    cin >> m;
+    for (int i = 0; i < m; i++) {
+        cin >> x >> y;
+        cout << solve(x, y) << endl;
+    }
+    return 0;
+}