#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));
#define mod 1000000007
inline int add(int a,int b){
int r=a+b;
while(r>=mod)r-=mod;
while(r<0)r+=mod;
return r;
}
inline int mult(int a,int b){
return (int)(((ll)a*b)%mod);
}
inline int rd(){
int x=0;
char ch=getchar_unlocked();
while(ch<'0'||ch>'9')ch=getchar_unlocked();
while(ch>='0'&&ch<='9'){
x=(x<<3)+(x<<1)+ch-'0';
ch=getchar_unlocked();
}
return x;
}
int n,m,a[505],b[505],memo[505][1005],c[1005][505],c2[505][505],w[1005][505],inv[505];
vector<int> v[1005],d;
int fp(int a,int x){
if(x==0)return 1;
int t=fp(a,x/2);
int r=mult(t,t);
if(x%2)r=mult(r,a);
return r;
}
int choose(int a,int b){
int r=1;
for(int i=a-b+1;i<=a;++i)r=mult(r,i);
for(int i=1;i<=b;++i)r=mult(r,inv[i]);
return r;
}
int dp(int i,int j){//covered up to the ith segment,now deciding for jth segment
if(i==n)return 1;
if(j==m)return (i!=0);
if(memo[i][j]!=-1)return memo[i][j];
int s=upper_bound(all(v[j]),i)-v[j].begin();
int ans=dp(i,j+1);
for(int t=s;t<sz(v[j]);++t){
ans=add(ans,mult(w[j][t-s+1],dp(v[j][t],j+1)));
}
return memo[i][j]=ans;
}
int main(){
sf("%d",&n);
for(int i=1;i<=n;++i){
sf("%d%d",&a[i],&b[i]);
d.pb(a[i]);d.pb(b[i]+1);
}
disc(d);m=sz(d);d.pb(d.back()+1);
for(int i=1;i<=n;++i){
for(int j=0;j<m;++j){
if(a[i]<=d[j]&&d[j]<=b[i])v[j].pb(i);
}
}
for(int i=1;i<=n;++i)inv[i]=fp(i,mod-2);
for(int i=0;i<m;++i){
int a=d[i+1]-d[i];
for(int b=1;b<=sz(v[i]);++b){
c[i][b]=choose(a,b);
}
}
for(int i=0;i<=n;++i){
for(int j=0;j<=i;++j){
c2[i][j]=choose(i,j);
}
}
for(int i=0;i<m;++i){
int a=d[i+1]-d[i];
for(int b=1;b<=sz(v[i]);++b){
for(int k=0;k<b;++k){
w[i][b]=add(w[i][b],mult(c[i][k+1],c2[b-1][k]));
}
}
}
memset(memo,-1,sizeof memo);
pf("%d\n",dp(0,0));
}
/*
2
1 2
2 3
*/
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:112:7: warning: unused variable 'a' [-Wunused-variable]
112 | int a=d[i+1]-d[i];
| ^
boat.cpp:88:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
88 | sf("%d",&n);
| ^
boat.cpp:90:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
90 | sf("%d%d",&a[i],&b[i]);
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
226 ms |
7508 KB |
Output is correct |
2 |
Correct |
228 ms |
7244 KB |
Output is correct |
3 |
Correct |
223 ms |
7484 KB |
Output is correct |
4 |
Correct |
232 ms |
7224 KB |
Output is correct |
5 |
Correct |
219 ms |
7308 KB |
Output is correct |
6 |
Correct |
227 ms |
7352 KB |
Output is correct |
7 |
Correct |
226 ms |
7364 KB |
Output is correct |
8 |
Correct |
214 ms |
7312 KB |
Output is correct |
9 |
Correct |
220 ms |
7248 KB |
Output is correct |
10 |
Correct |
215 ms |
7240 KB |
Output is correct |
11 |
Correct |
215 ms |
7236 KB |
Output is correct |
12 |
Correct |
219 ms |
7284 KB |
Output is correct |
13 |
Correct |
229 ms |
7316 KB |
Output is correct |
14 |
Correct |
215 ms |
7228 KB |
Output is correct |
15 |
Correct |
223 ms |
7232 KB |
Output is correct |
16 |
Correct |
224 ms |
3988 KB |
Output is correct |
17 |
Correct |
211 ms |
4036 KB |
Output is correct |
18 |
Correct |
209 ms |
3952 KB |
Output is correct |
19 |
Correct |
213 ms |
4108 KB |
Output is correct |
20 |
Correct |
211 ms |
4036 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
226 ms |
7508 KB |
Output is correct |
2 |
Correct |
228 ms |
7244 KB |
Output is correct |
3 |
Correct |
223 ms |
7484 KB |
Output is correct |
4 |
Correct |
232 ms |
7224 KB |
Output is correct |
5 |
Correct |
219 ms |
7308 KB |
Output is correct |
6 |
Correct |
227 ms |
7352 KB |
Output is correct |
7 |
Correct |
226 ms |
7364 KB |
Output is correct |
8 |
Correct |
214 ms |
7312 KB |
Output is correct |
9 |
Correct |
220 ms |
7248 KB |
Output is correct |
10 |
Correct |
215 ms |
7240 KB |
Output is correct |
11 |
Correct |
215 ms |
7236 KB |
Output is correct |
12 |
Correct |
219 ms |
7284 KB |
Output is correct |
13 |
Correct |
229 ms |
7316 KB |
Output is correct |
14 |
Correct |
215 ms |
7228 KB |
Output is correct |
15 |
Correct |
223 ms |
7232 KB |
Output is correct |
16 |
Correct |
224 ms |
3988 KB |
Output is correct |
17 |
Correct |
211 ms |
4036 KB |
Output is correct |
18 |
Correct |
209 ms |
3952 KB |
Output is correct |
19 |
Correct |
213 ms |
4108 KB |
Output is correct |
20 |
Correct |
211 ms |
4036 KB |
Output is correct |
21 |
Correct |
744 ms |
7832 KB |
Output is correct |
22 |
Correct |
729 ms |
8008 KB |
Output is correct |
23 |
Correct |
684 ms |
7836 KB |
Output is correct |
24 |
Correct |
736 ms |
7840 KB |
Output is correct |
25 |
Correct |
745 ms |
7844 KB |
Output is correct |
26 |
Correct |
1305 ms |
8048 KB |
Output is correct |
27 |
Correct |
1305 ms |
8208 KB |
Output is correct |
28 |
Correct |
1312 ms |
8132 KB |
Output is correct |
29 |
Correct |
1280 ms |
8176 KB |
Output is correct |
30 |
Correct |
224 ms |
7288 KB |
Output is correct |
31 |
Correct |
223 ms |
7376 KB |
Output is correct |
32 |
Correct |
228 ms |
7248 KB |
Output is correct |
33 |
Correct |
233 ms |
7392 KB |
Output is correct |
34 |
Correct |
225 ms |
7252 KB |
Output is correct |
35 |
Correct |
218 ms |
7236 KB |
Output is correct |
36 |
Correct |
219 ms |
7268 KB |
Output is correct |
37 |
Correct |
218 ms |
7248 KB |
Output is correct |
38 |
Correct |
220 ms |
7368 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
3280 KB |
Output is correct |
2 |
Correct |
7 ms |
3276 KB |
Output is correct |
3 |
Correct |
8 ms |
3276 KB |
Output is correct |
4 |
Correct |
8 ms |
3380 KB |
Output is correct |
5 |
Correct |
11 ms |
3380 KB |
Output is correct |
6 |
Correct |
15 ms |
3276 KB |
Output is correct |
7 |
Correct |
15 ms |
3400 KB |
Output is correct |
8 |
Correct |
16 ms |
3400 KB |
Output is correct |
9 |
Correct |
15 ms |
3396 KB |
Output is correct |
10 |
Correct |
16 ms |
3500 KB |
Output is correct |
11 |
Correct |
9 ms |
3336 KB |
Output is correct |
12 |
Correct |
9 ms |
3260 KB |
Output is correct |
13 |
Correct |
9 ms |
3368 KB |
Output is correct |
14 |
Correct |
9 ms |
3384 KB |
Output is correct |
15 |
Correct |
10 ms |
3272 KB |
Output is correct |
16 |
Correct |
7 ms |
3020 KB |
Output is correct |
17 |
Correct |
7 ms |
3020 KB |
Output is correct |
18 |
Correct |
6 ms |
3020 KB |
Output is correct |
19 |
Correct |
6 ms |
3020 KB |
Output is correct |
20 |
Correct |
7 ms |
2892 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
226 ms |
7508 KB |
Output is correct |
2 |
Correct |
228 ms |
7244 KB |
Output is correct |
3 |
Correct |
223 ms |
7484 KB |
Output is correct |
4 |
Correct |
232 ms |
7224 KB |
Output is correct |
5 |
Correct |
219 ms |
7308 KB |
Output is correct |
6 |
Correct |
227 ms |
7352 KB |
Output is correct |
7 |
Correct |
226 ms |
7364 KB |
Output is correct |
8 |
Correct |
214 ms |
7312 KB |
Output is correct |
9 |
Correct |
220 ms |
7248 KB |
Output is correct |
10 |
Correct |
215 ms |
7240 KB |
Output is correct |
11 |
Correct |
215 ms |
7236 KB |
Output is correct |
12 |
Correct |
219 ms |
7284 KB |
Output is correct |
13 |
Correct |
229 ms |
7316 KB |
Output is correct |
14 |
Correct |
215 ms |
7228 KB |
Output is correct |
15 |
Correct |
223 ms |
7232 KB |
Output is correct |
16 |
Correct |
224 ms |
3988 KB |
Output is correct |
17 |
Correct |
211 ms |
4036 KB |
Output is correct |
18 |
Correct |
209 ms |
3952 KB |
Output is correct |
19 |
Correct |
213 ms |
4108 KB |
Output is correct |
20 |
Correct |
211 ms |
4036 KB |
Output is correct |
21 |
Correct |
744 ms |
7832 KB |
Output is correct |
22 |
Correct |
729 ms |
8008 KB |
Output is correct |
23 |
Correct |
684 ms |
7836 KB |
Output is correct |
24 |
Correct |
736 ms |
7840 KB |
Output is correct |
25 |
Correct |
745 ms |
7844 KB |
Output is correct |
26 |
Correct |
1305 ms |
8048 KB |
Output is correct |
27 |
Correct |
1305 ms |
8208 KB |
Output is correct |
28 |
Correct |
1312 ms |
8132 KB |
Output is correct |
29 |
Correct |
1280 ms |
8176 KB |
Output is correct |
30 |
Correct |
224 ms |
7288 KB |
Output is correct |
31 |
Correct |
223 ms |
7376 KB |
Output is correct |
32 |
Correct |
228 ms |
7248 KB |
Output is correct |
33 |
Correct |
233 ms |
7392 KB |
Output is correct |
34 |
Correct |
225 ms |
7252 KB |
Output is correct |
35 |
Correct |
218 ms |
7236 KB |
Output is correct |
36 |
Correct |
219 ms |
7268 KB |
Output is correct |
37 |
Correct |
218 ms |
7248 KB |
Output is correct |
38 |
Correct |
220 ms |
7368 KB |
Output is correct |
39 |
Correct |
9 ms |
3280 KB |
Output is correct |
40 |
Correct |
7 ms |
3276 KB |
Output is correct |
41 |
Correct |
8 ms |
3276 KB |
Output is correct |
42 |
Correct |
8 ms |
3380 KB |
Output is correct |
43 |
Correct |
11 ms |
3380 KB |
Output is correct |
44 |
Correct |
15 ms |
3276 KB |
Output is correct |
45 |
Correct |
15 ms |
3400 KB |
Output is correct |
46 |
Correct |
16 ms |
3400 KB |
Output is correct |
47 |
Correct |
15 ms |
3396 KB |
Output is correct |
48 |
Correct |
16 ms |
3500 KB |
Output is correct |
49 |
Correct |
9 ms |
3336 KB |
Output is correct |
50 |
Correct |
9 ms |
3260 KB |
Output is correct |
51 |
Correct |
9 ms |
3368 KB |
Output is correct |
52 |
Correct |
9 ms |
3384 KB |
Output is correct |
53 |
Correct |
10 ms |
3272 KB |
Output is correct |
54 |
Correct |
7 ms |
3020 KB |
Output is correct |
55 |
Correct |
7 ms |
3020 KB |
Output is correct |
56 |
Correct |
6 ms |
3020 KB |
Output is correct |
57 |
Correct |
6 ms |
3020 KB |
Output is correct |
58 |
Correct |
7 ms |
2892 KB |
Output is correct |
59 |
Correct |
951 ms |
8332 KB |
Output is correct |
60 |
Correct |
848 ms |
8256 KB |
Output is correct |
61 |
Correct |
808 ms |
8284 KB |
Output is correct |
62 |
Correct |
902 ms |
8600 KB |
Output is correct |
63 |
Correct |
866 ms |
8308 KB |
Output is correct |
64 |
Correct |
1649 ms |
8784 KB |
Output is correct |
65 |
Correct |
1573 ms |
8704 KB |
Output is correct |
66 |
Correct |
1631 ms |
8644 KB |
Output is correct |
67 |
Correct |
1620 ms |
8640 KB |
Output is correct |
68 |
Correct |
1629 ms |
8696 KB |
Output is correct |
69 |
Correct |
913 ms |
8252 KB |
Output is correct |
70 |
Correct |
867 ms |
8224 KB |
Output is correct |
71 |
Correct |
855 ms |
8324 KB |
Output is correct |
72 |
Correct |
864 ms |
8288 KB |
Output is correct |
73 |
Correct |
899 ms |
8324 KB |
Output is correct |
74 |
Correct |
316 ms |
4160 KB |
Output is correct |
75 |
Correct |
309 ms |
4172 KB |
Output is correct |
76 |
Correct |
338 ms |
4164 KB |
Output is correct |
77 |
Correct |
335 ms |
4352 KB |
Output is correct |
78 |
Correct |
336 ms |
4288 KB |
Output is correct |