#include <bits/stdc++.h>
using namespace std;
#define int long long
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) {
return '"' + s + '"';
}
string to_string(const char* s) {
return to_string((string) s);
}
string to_string(bool b) {
return (b ? "true" : "false");
}
string to_string(vector<bool> v) {
bool first = true;
string res = "{";
for (int i = 0; i < static_cast<int>(v.size()); i++) {
if (!first) {
res += ", ";
}
first = false;
res += to_string(v[i]);
}
res += "}";
return res;
}
template <size_t N>
string to_string(bitset<N> v) {
string res = "";
for (size_t i = 0; i < N; i++) {
res += static_cast<char>('0' + v[i]);
}
return res;
}
template <typename A>
string to_string(A v) {
bool first = true;
string res = "{";
for (const auto &x : v) {
if (!first) {
res += ", ";
}
first = false;
res += to_string(x);
}
res += "}";
return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
cerr << " " << to_string(H);
debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
#define all(a) (a).begin(), (a).end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define reps(i, s, n) for (int i = s; i < (n); ++i)
#define pb push_back
#define sz(a) (int) (a.size())
const int mod = 1e9 + 7;
void solve() {
int n;
cin >> n;
vector<int> l(n), r(n), cs;
rep(i, n) {
cin >> l[i] >> r[i];
cs.pb(l[i]);
cs.pb(r[i] - 1);
cs.pb(r[i]);
cs.pb(r[i] + 1);
}
sort(all(cs));
cs.erase(unique(all(cs)), cs.end());
vector<pair<int, int>> segs;
rep(i, sz(cs) - 1) {
segs.emplace_back(cs[i], cs[i + 1] - 1);
}
segs.emplace_back(cs.back(), cs.back());
debug(segs);
auto add = [&] (int &a, int b) -> void {
(a += b) %= mod;
};
auto mul = [&] (int a, int b) {
return a * b % mod;
};
auto binpow = [&] (int a, int n) {
int res = 1;
while (n) {
if (n % 2) {
res = mul(res, a);
}
a = mul(a, a);
n /= 2;
}
return res;
};
auto inv = [&] (int val) {
return binpow(val, mod - 2);
};
vector<int> f(n + 1), rf(n + 1);
f[0] = rf[0] = 1;
reps(i, 1, n + 1) {
f[i] = mul(f[i - 1], i);
rf[i] = inv(f[i]);
}
auto C = [&] (int n, int k) {
int res = 1;
reps(i, 1, k + 1) {
res = mul(res, n - k + i);
}
return mul(res, rf[k]);
};
auto sub = [&] (int a, int b) {
a -= b;
if (a < 0) a += mod;
return a;
};
vector<vector<int>> dp(n, vector<int> (sz(cs)));
rep(pos, sz(segs)) {
if (segs[pos].first >= l[0] && segs[pos].second <= r[0]) {
dp[0][pos] = segs[pos].second - segs[pos].first + 1;
}
}
reps(i, 1, n) {
rep(pos, sz(segs)) {
if (segs[pos].first < l[i] || segs[pos].second > r[i]) continue;
int len = segs[pos].second - segs[pos].first + 1;
add(dp[i][pos], len);
rep(prev, pos) {
add(dp[i][pos], mul(len, dp[i - 1][prev]));
}
int cur = 0;
for (int j = i; j >= i; j--) {
reps(cnt, 2, min(cur + 1, len + 1)) {
rep(prev, pos) {
add(dp[i][pos], mul(C(len, cnt), dp[j][prev]));
}
}
if (segs[pos].first >= l[j] && segs[pos].second <= r[j]) {
cur++;
}
}
}
debug(i, dp);
}
int res = 0;
reps(i, 0, n) {
rep(j, sz(segs)) {
add(res, dp[i][j]);
}
}
cout << res;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
Compilation message
boat.cpp: In function 'void solve()':
boat.cpp:91:22: warning: statement has no effect [-Wunused-value]
91 | #define debug(...) 42
| ^~
boat.cpp:122:5: note: in expansion of macro 'debug'
122 | debug(segs);
| ^~~~~
boat.cpp:91:22: warning: statement has no effect [-Wunused-value]
91 | #define debug(...) 42
| ^~
boat.cpp:195:7: note: in expansion of macro 'debug'
195 | debug(i, dp);
| ^~~~~
boat.cpp:163:10: warning: variable 'sub' set but not used [-Wunused-but-set-variable]
163 | auto sub = [&] (int a, int b) {
| ^~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
9 ms |
6228 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
9 ms |
6228 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
13 ms |
596 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
9 ms |
6228 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
