///
/// ♪ Pizza mozzarella rella rella rella... ♪
///
#define _USE_MATH_DEFINES
#define FAST ios::sync_with_stdio(false),cin.tie(0);
#include <bits/stdc++.h>
#define Loop(x, l, r) for(int x = (l); x < (r); ++x)
#define LoopR(x, l, r) for(int x = (r)-1; x >= (l); --x)
#define all(x) x.begin(), x.end()
#define Kill(x) exit((cout << (x) << '\n', 0))
#define YN(flag) ((flag)? "YES": "NO")
#define F first
#define S second
typedef long long ll;
typedef unsigned long long ull;
typedef std::pair<int,int> pii;
typedef std::pair<ll ,ll > pll;
using namespace std;
const int mod = 1e9 + 7;
const int N = 512;
vector<int> cmp;
int l[N], r[N];
int n;
ll dp[N][2*N];
ll fct[2*N], fci[2*N];
ll inv[2*N];
ll Inv(ll x){
ll ans = 1;
for(ll y = mod-2; y; y >>= 1){
if(y&1) ans = ans*x % mod;
x = x*x % mod;
}
return ans;
}
int main()
{
FAST;
cin >> n;
inv[0] = fci[0] = fct[0] = 1;
Loop(i,1,2*N) fct[i] = fct[i-1]*i % mod, fci[i] = Inv(fct[i]), inv[i] = Inv(i);
Loop(i,0,n)
{
cin >> l[i] >> r[i];
++r[i];
cmp.push_back(l[i]);
cmp.push_back(r[i]);
}
cmp.push_back(1e9+10);
sort(all(cmp)); cmp.resize(unique(all(cmp))-cmp.begin());
Loop(i,0,2*N) dp[0][i] = 1;
Loop(i,0,n)
{
Loop(j,0,cmp.size()-1)
{
ll m = cmp[j+1] - cmp[j];
ll X = 1;
int k = 0;
LoopR(p,0,i+1)
{
if(r[i] <= cmp[j] || cmp[j+1] <= l[i]) continue;
X = X*(m+k) % mod;
X = X*inv[k+1] % mod;
++k;
dp[i+1][j] = (dp[i+1][j] + X*dp[p][j]) % mod;
}
}
ll sum = 1;
Loop(j,0,cmp.size())
sum += dp[i+1][j],
dp[i+1][j] = sum - dp[i+1][j];
}
//Loop(i,0,n+1) {Loop(j,0,cmp.size()) cout << dp[i][j] << ' '; cout << '\n';}
cout << (dp[n][cmp.size()-1]+mod-1)%mod << '\n';
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:8:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | #define Loop(x, l, r) for(int x = (l); x < (r); ++x)
| ^
boat.cpp:58:9: note: in expansion of macro 'Loop'
58 | Loop(j,0,cmp.size()-1)
| ^~~~
boat.cpp:8:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | #define Loop(x, l, r) for(int x = (l); x < (r); ++x)
| ^
boat.cpp:74:9: note: in expansion of macro 'Loop'
74 | Loop(j,0,cmp.size())
| ^~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
153 ms |
4292 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
153 ms |
4292 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
7 ms |
716 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
153 ms |
4292 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |