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OI-codes/LibreOJ/2279/2279.cpp

115 lines
2.5 KiB
C++

#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;
}