#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
const int mod = (int)1e9+7;
struct Mint{
int val;
Mint(){ val = 0; }
Mint(long long v){
val = (-mod <= v && v < mod) ? v : v%mod;
if(val < 0) val+= mod;
}
// operators
Mint operator-(){return Mint(-val);}
Mint& operator+=(const Mint& other){ val+=other.val; if(val >= mod) val-=mod; return *this;}
Mint& operator-=(const Mint& other){ val-=other.val; if(val < 0) val+=mod; return *this;}
Mint& operator*=(const Mint& other){ val=((long long)val*other.val)%mod; return *this;}
friend Mint binpow(Mint a, long long p){
Mint res(1);
while(p > 0){
if(p&1) res*=a; a*=a; p>>=1;
}
return res;
}
friend Mint inv(Mint a){ return binpow(a, mod-2); }
Mint& operator/=(const Mint &other){ return (*this)*=inv(other);}
friend Mint operator+(Mint a, const Mint& b){ return a+=b; }
friend Mint operator-(Mint a, const Mint& b){ return a-=b; }
friend Mint operator*(Mint a, const Mint& b){ return a*=b; }
friend Mint operator/(Mint a, const Mint& b){ return a/=b; }
bool operator==(const Mint &other){return val == other.val;}
bool operator!=(const Mint &other){return val != other.val;}
bool operator<(const Mint &other){return val < other.val;}
// io
friend ostream& operator<<(ostream &out, Mint &a){ return out << a.val; }
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
vector<Mint> I(1000);
FOR(i, 1, 1000, 1) I[i] = Mint(1) / Mint(i);
int n; cin >> n;
vector<array<int, 2>> orig_ranges;
vi comp;
REP(i, n){
int a, b;
cin >> a >> b;
b++; // [a, b)
orig_ranges.pb({a, b});
comp.pb(a);
comp.pb(b);
}
sort(all(comp));
comp.erase(unique(all(comp)), comp.end());
vector<array<ll, 2>> ranges(n);
REP(i, n){
int l = lower_bound(all(comp), orig_ranges[i][0]) - comp.begin();
int r = lower_bound(comp.begin() + l + 1, comp.end(), orig_ranges[i][1]) - comp.begin();
r--;
ranges[i] = {l + 1, r + 1};
//cout << l + 1 << " " << r + 1 << endl;
}
int m = (int)comp.size() + 2;
vector<vector<Mint>> dp(n + 5, vector<Mint>(m + 5, Mint(0))); // dp[i][j] - divide first i elements into j groups
REP(i, m + 4){
dp[0][i] = Mint(1);
}
FOR(i, 1, n+1, 1){
FOR(j, ranges[i - 1][0], ranges[i - 1][1] + 1, 1){
int len = comp[j] - comp[j - 1];
Mint prod = len;
int cnt = 1;
dp[i][j] += Mint(len) * dp[i-1][j-1];
FORD(k, i - 1, 1, 1){
if(j >= ranges[k - 1][0] && ranges[k - 1][1] > j){
prod *= Mint(len + cnt);
prod *= I[cnt + 1];
cnt++;
}
dp[i][j] += prod * dp[k-1][j-1];
}
}
dp[i][0] = Mint(1);
FOR(j, 1, m+1, 1){
dp[i][j] += dp[i][j-1];
}
}
Mint ans = dp[n][m] - Mint(1);
cout << ans << "\n";
return 0;
}
Compilation message
boat.cpp: In function 'Mint binpow(Mint, long long int)':
boat.cpp:101:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
101 | if(p&1) res*=a; a*=a; p>>=1;
| ^~
boat.cpp:101:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
101 | if(p&1) res*=a; a*=a; p>>=1;
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
4 ms |
2412 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
4 ms |
2412 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
3 ms |
492 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
4 ms |
2412 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
