#include <bits/stdc++.h>
#define ll long long
#define pii pair<ll, ll>
#define X first
#define Y second
#define pb push_back
using namespace std;
const int N = 1010;
const ll MOD = 1e9 + 7;
ll n, intcnt, l[N], r[N];
ll siz[N], fact[N], povrh[N][N], calc[N][N];
ll dp[N][N];
int u[N][N];
vector<pii> intv;
vector<ll> v;
ll add(ll a, ll b){
return (a + b >= MOD ? a + b - MOD : a + b);
}
ll mult(ll a, ll b){
return a * b % MOD;
}
ll fastpow(ll b, ll e){
ll ret = 1;
while(e){
if(e & 1) ret = mult(ret, b);
b = mult(b, b);
e >>= 1;
}
return ret;
}
ll divd(ll a, ll b){
return mult(a, fastpow(b, MOD - 2));
}
void precompute(){
fact[0] = 1;
for(int i = 1; i < N; i++) fact[i] = mult(fact[i - 1], i);
for(int i = 0; i < N / 2; i++) for(int j = 0; j <= i; j++) povrh[i][j] = divd(fact[i], mult(fact[j], fact[i - j]));
for(int i = 0; i < intcnt; i++){
ll sfact = 1;
for(ll k = 1; k <= n; k++){
ll sfact = 1;
for(ll j = 1; j <= min(k, siz[i]); j++){
sfact = mult(sfact, siz[i] - j + 1);
calc[i][k] = add(calc[i][k], mult(povrh[k - 1][j - 1], divd(sfact, fact[j])));
}
}
}
}
ll DP(int x, int b){
if(b >= intcnt) return 1;
if(dp[x][b] != -1) return dp[x][b];
dp[x][b] = DP(x, b + 1);
int cnt = 0;
for(int i = x; i < n; i++){
cnt += u[i][b];
if(u[i][b]) dp[x][b] = add(dp[x][b], mult(calc[b][cnt], DP(i + 1, b + 1)));
}
// printf("%d %lld %lld s: %lld\n", x, b, dp[x][b], calc[b][2]);
return dp[x][b];
}
int main(){
for(int i = 0; i < N; i++) for(int j = 0; j < N; j++) dp[i][j] = -1;
scanf("%d", &n);
for(int i = 0; i < n; i++){
scanf("%lld%lld", &l[i], &r[i]);
v.pb(l[i]);
v.pb(r[i]);
}
sort(v.begin(), v.end());
v.resize(unique(v.begin(), v.end()) - v.begin());
for(int i = 0; i < v.size(); i++){
if(i != 0 && v[i - 1] < v[i] - 1){
intv.pb({v[i - 1] + 1, v[i] - 1});
}
intv.pb({v[i], v[i]});
}
intcnt = intv.size();
for(int i = 0; i < intcnt; i++) siz[i] = intv[i].Y - intv[i].X + 1;
for(int i = 0; i < n; i++){
for(ll j = 0; j < intcnt; j++){
if(intv[j].X >= l[i] && intv[j].Y <= r[i]){
u[i][j] = true;
}
}
// printf("%d %d %d\n", i, poc[i], kraj[i]);
}
precompute();
printf("%lld\n", add(DP(0, 0), MOD - 1));
return 0;
}
Compilation message
boat.cpp: In function 'void precompute()':
boat.cpp:51:6: warning: unused variable 'sfact' [-Wunused-variable]
51 | ll sfact = 1;
| ^~~~~
boat.cpp: In function 'int main()':
boat.cpp:81:10: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
81 | scanf("%d", &n);
| ~^ ~~
| | |
| | long long int*
| int*
| %lld
boat.cpp:92:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
92 | for(int i = 0; i < v.size(); i++){
| ~~^~~~~~~~~~
boat.cpp:81:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
81 | scanf("%d", &n);
| ~~~~~^~~~~~~~~~
boat.cpp:84:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
84 | scanf("%lld%lld", &l[i], &r[i]);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2079 ms |
14852 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2079 ms |
14852 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
166 ms |
13636 KB |
Output is correct |
2 |
Correct |
184 ms |
13564 KB |
Output is correct |
3 |
Correct |
180 ms |
13644 KB |
Output is correct |
4 |
Correct |
164 ms |
13576 KB |
Output is correct |
5 |
Correct |
180 ms |
13716 KB |
Output is correct |
6 |
Correct |
172 ms |
13616 KB |
Output is correct |
7 |
Correct |
164 ms |
13656 KB |
Output is correct |
8 |
Correct |
166 ms |
13656 KB |
Output is correct |
9 |
Correct |
168 ms |
13632 KB |
Output is correct |
10 |
Correct |
168 ms |
13700 KB |
Output is correct |
11 |
Correct |
170 ms |
13636 KB |
Output is correct |
12 |
Correct |
163 ms |
13696 KB |
Output is correct |
13 |
Correct |
161 ms |
13680 KB |
Output is correct |
14 |
Correct |
164 ms |
13656 KB |
Output is correct |
15 |
Correct |
161 ms |
13596 KB |
Output is correct |
16 |
Correct |
92 ms |
12544 KB |
Output is correct |
17 |
Correct |
85 ms |
12508 KB |
Output is correct |
18 |
Correct |
83 ms |
12540 KB |
Output is correct |
19 |
Correct |
82 ms |
12536 KB |
Output is correct |
20 |
Correct |
85 ms |
12564 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2079 ms |
14852 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |