이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
static constexpr int P = 1e9 + 7;
auto add = [](int &x, int y) {
x += y;
if (x >= P) x -= P;
if (x < 0) x += P;
};
int n, m;
cin >> n >> m;
vector<int> enforce0(n, -1); // enforces s[i] >= s[i + 1]
vector<int> enforce1(n, -1); // enforces s[i] <= s[i + 1]
for (int i = 0; i < m; i++) {
int a, b;
cin >> a >> b;
a--;
b--;
if (a < b) enforce0[a] = max(enforce0[a], b);
else enforce1[b] = max(enforce1[b], a);
}
vector<int> all(n);
iota(all.begin(), all.end(), 0);
set<int> s0(all.begin(), all.end());
set<int> s1(all.begin(), all.end());
vector<vector<int>> dp(n, vector<int>(26, 0));
vector<vector<int>> upper(n, vector<int>(26, 0));
vector<vector<int>> lower(n, vector<int>(26, 0));
dp[n - 1] = vector<int>(26, 1);
int f = accumulate(dp[n - 1].begin(), dp[n - 1].end(), 0LL) % P;
auto update = [&](int i) {
for (int c = 24; c >= 0; c--) {
upper[i][c] = upper[i][c + 1];
add(upper[i][c], dp[i][c + 1]);
}
for (int c = 1; c < 26; c++) {
lower[i][c] = lower[i][c - 1];
add(lower[i][c], dp[i][c - 1]);
}
};
update(n - 1);
for (int i = n - 2; i >= 0; i--) {
vector<int> adj0;
vector<int> adj1;
if (enforce0[i] != -1) {
while (true) {
auto it = s0.upper_bound(i);
if (it == s0.end() || *it > enforce0[i]) break;
adj0.push_back(*it);
s0.erase(it);
}
}
if (enforce1[i] != -1) {
while (true) {
auto it = s1.upper_bound(i);
if (it == s1.end() || *it > enforce1[i]) break;
adj1.push_back(*it);
s1.erase(it);
}
}
for (int c = 0; c < 26; c++) {
add(dp[i][c], f);
for (int j : adj0) {
add(dp[i][c], -upper[j][c]);
}
for (int j : adj1) {
add(dp[i][c], -lower[j][c]);
}
}
update(i);
f = accumulate(dp[i].begin(), dp[i].end(), 0LL) % P;
}
cout << f << '\n';
}
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |