#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {
cerr<<vars<<" = ";
string delim="";
(...,(cerr<<delim<<values,delim=", "));
cerr<<"\n";
}
#else
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {}
#endif
#define pb push_back
#define sz(x) (int)(x.size())
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<typename T> inline void maxa(T& a,T b){a=max(a,b);}
template<typename T> inline void mina(T& a,T b){a=min(a,b);}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mxN=2e5+5; //make sure this is right
const int mod=1e9+7;
struct RANK{
vector<int> all;
int get(int x){return lower_bound(all.begin(),all.end(),x)-all.begin()+1;}
void add(int x){all.pb(x);}
void fix(){
sort(all.begin(),all.end());
all.resize(unique(all.begin(),all.end())-all.begin());
}
} rnk;
ll dp[505][1005],a[505],b[505];
int main(){
cin.sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
#endif
rnk.add(1);
int n; cin>>n;
for(int i=1;i<=n;i++){
cin>>a[i]>>b[i];
rnk.add(a[i]);
rnk.add(b[i]);
}
rnk.fix();
for(int i=1;i<=sz(rnk.all);i++)
dp[0][i]=1;
for(int i=1;i<=n;i++){
int A=rnk.get(a[i]);
int B=rnk.get(b[i]);
for(int j=1;j<=sz(rnk.all);j++){
dp[i][j]=dp[i-1][j];
int hi=min(rnk.all[j-1]-1,B);
int lo=max(j==1?1:rnk.all[j-2],A);
if(lo>hi) continue;
dp[i][j]+=(dp[i-1][j-1]*(hi-lo+1))%mod;
dp[i][j]%=mod;
}
}
ll ans=0;
for(int i=1;i<=sz(rnk.all);i++)
ans=(ans+dp[n][i])%mod;
cout<<ans<<"\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
2 ms |
4172 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
2 ms |
4172 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
840 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
2 ms |
4172 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |