#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e18 + 10;
const ld EPS = 1e-9;
void solve() {
int n; cin >> n;
vll ab(n); for (auto &[x, y] : ab) cin >> x >> y;
set<ll> s = {0, INF}; for (auto [x, y] : ab) s.insert(x), s.insert(y);
vl uabs(all(s));
vii idx_uabs(n);
for (int i=0; i<n; i++) {
idx_uabs[i].first = lower_bound(all(uabs), ab[i].first) - uabs.begin();
idx_uabs[i].second = lower_bound(all(uabs), ab[i].second) - uabs.begin();
}
int m = uabs.size();
vvl dp(n + 1, vl(m + 1, -1));
function<ll(int, int)> f = [&](int idx, int mn_take_idx) -> ll {
assert(idx < n);
assert(mn_take_idx < m);
auto [a, b] = ab[idx];
ll mn_take = uabs[mn_take_idx];
if (idx == n - 1) {
if (mn_take < a) return (b - a + 1 + 1) % MOD;
if (a <= mn_take && mn_take <= b) return (b - mn_take + 1 + 1) % MOD;
return 1;
}
ll &x = dp[idx][mn_take_idx];
if (x != -1) return x;
x = f(idx + 1, mn_take_idx);
for (int take_idx=idx_uabs[idx].second; take_idx>=max(mn_take_idx, idx_uabs[idx].first); take_idx--) {
if (take_idx == idx_uabs[idx].second) x += f(idx + 1, take_idx + 1);
else x += (((uabs[take_idx + 1] - uabs[take_idx]) % MOD) * f(idx + 1, take_idx + 1)) % MOD;
x %= MOD;
}
// if (mn_take > b) return x;
// for (int take_idx=max(mn_take_idx, idx_uabs[idx].first); take_idx<=idx_uabs[idx].second; take_idx++) {
// x += f(idx + 1, take_idx + 1);
// x %= MOD;
// }
// ll take_idx = mn_take_idx;
// for (ll take=max(a, mn_take); take<=b; take++) {
// while (uabs[take_idx] <= take) take_idx++;
// x += f(idx + 1, take_idx);
// x %= MOD;
// }
return x;
};
cout << (f(0, 0) - 1 + MOD) % MOD << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
/* cin >> test_cases; */
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:150:11: warning: unused variable 'start' [-Wunused-variable]
150 | clock_t start = clock();
| ^~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2388 KB |
Output is correct |
2 |
Correct |
4 ms |
2388 KB |
Output is correct |
3 |
Correct |
5 ms |
2388 KB |
Output is correct |
4 |
Correct |
6 ms |
2388 KB |
Output is correct |
5 |
Correct |
5 ms |
2388 KB |
Output is correct |
6 |
Correct |
5 ms |
2388 KB |
Output is correct |
7 |
Correct |
5 ms |
2388 KB |
Output is correct |
8 |
Correct |
4 ms |
2388 KB |
Output is correct |
9 |
Correct |
4 ms |
2388 KB |
Output is correct |
10 |
Correct |
4 ms |
2388 KB |
Output is correct |
11 |
Correct |
4 ms |
2388 KB |
Output is correct |
12 |
Correct |
4 ms |
2388 KB |
Output is correct |
13 |
Correct |
4 ms |
2388 KB |
Output is correct |
14 |
Correct |
5 ms |
2388 KB |
Output is correct |
15 |
Correct |
4 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
724 KB |
Output is correct |
17 |
Correct |
2 ms |
724 KB |
Output is correct |
18 |
Correct |
1 ms |
724 KB |
Output is correct |
19 |
Correct |
2 ms |
724 KB |
Output is correct |
20 |
Correct |
1 ms |
724 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2388 KB |
Output is correct |
2 |
Correct |
4 ms |
2388 KB |
Output is correct |
3 |
Correct |
5 ms |
2388 KB |
Output is correct |
4 |
Correct |
6 ms |
2388 KB |
Output is correct |
5 |
Correct |
5 ms |
2388 KB |
Output is correct |
6 |
Correct |
5 ms |
2388 KB |
Output is correct |
7 |
Correct |
5 ms |
2388 KB |
Output is correct |
8 |
Correct |
4 ms |
2388 KB |
Output is correct |
9 |
Correct |
4 ms |
2388 KB |
Output is correct |
10 |
Correct |
4 ms |
2388 KB |
Output is correct |
11 |
Correct |
4 ms |
2388 KB |
Output is correct |
12 |
Correct |
4 ms |
2388 KB |
Output is correct |
13 |
Correct |
4 ms |
2388 KB |
Output is correct |
14 |
Correct |
5 ms |
2388 KB |
Output is correct |
15 |
Correct |
4 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
724 KB |
Output is correct |
17 |
Correct |
2 ms |
724 KB |
Output is correct |
18 |
Correct |
1 ms |
724 KB |
Output is correct |
19 |
Correct |
2 ms |
724 KB |
Output is correct |
20 |
Correct |
1 ms |
724 KB |
Output is correct |
21 |
Incorrect |
833 ms |
4056 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
7 ms |
468 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2388 KB |
Output is correct |
2 |
Correct |
4 ms |
2388 KB |
Output is correct |
3 |
Correct |
5 ms |
2388 KB |
Output is correct |
4 |
Correct |
6 ms |
2388 KB |
Output is correct |
5 |
Correct |
5 ms |
2388 KB |
Output is correct |
6 |
Correct |
5 ms |
2388 KB |
Output is correct |
7 |
Correct |
5 ms |
2388 KB |
Output is correct |
8 |
Correct |
4 ms |
2388 KB |
Output is correct |
9 |
Correct |
4 ms |
2388 KB |
Output is correct |
10 |
Correct |
4 ms |
2388 KB |
Output is correct |
11 |
Correct |
4 ms |
2388 KB |
Output is correct |
12 |
Correct |
4 ms |
2388 KB |
Output is correct |
13 |
Correct |
4 ms |
2388 KB |
Output is correct |
14 |
Correct |
5 ms |
2388 KB |
Output is correct |
15 |
Correct |
4 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
724 KB |
Output is correct |
17 |
Correct |
2 ms |
724 KB |
Output is correct |
18 |
Correct |
1 ms |
724 KB |
Output is correct |
19 |
Correct |
2 ms |
724 KB |
Output is correct |
20 |
Correct |
1 ms |
724 KB |
Output is correct |
21 |
Incorrect |
833 ms |
4056 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |