#include <bits/stdc++.h>
using namespace std;
#define pb push_back
const int len = 505, mod = 1e9+7;
int n, m = 0;
int po[2*len], dp[2][2*len][len][2], bi[2*len][len], l[len], r[len];
vector<int> vec;
int add(int a, int b){
return (a+b)%mod;
}
int mul(int a, int b){
return (a*1LL*b)%mod;
}
int pw(int a, int b){
if (b == 0) return 1;
if (b%2 == 0) return pw(mul(a, a), b/2);
return mul(a, pw(mul(a, a), b/2));
}
int main(){
scanf("%d", &n);
for (int i = 1; i <= n; i++){
scanf("%d %d", &l[i], &r[i]);
vec.pb(l[i]), vec.pb(r[i]);
}
sort(vec.begin(), vec.end());
for (int i = 0; i < vec.size(); i++)
if (vec[i] != po[m])
po[++m] = vec[i];
//for (int i = 0; i <= m; i++)
// printf("i = %d, poi = %d\n", i, po[i]);
for (int i = 0; i <= m; i++){
bi[i][0] = 1;
int s = po[i]-po[i-1] - 1;
for (int k = 1; k <= min(s, n); k++)
bi[i][k] = mul(bi[i][k-1], mul(s-k+1, pw(k, mod-2)));
}
for (int i = 0; i <= n; i++)
for (int j = 0; j <= m+1; j++)
for (int k = 0; k <= i; k++)
for (int t = 0; t < 2; t++){
if ((i == 0 || j == 0) && (k == 0)){
dp[i&1][j][k][t] = 1;
continue;
}
int ans = 0;
if (k == 0){
for (int x = 0; x <= i; x++){
ans = add(ans, mul(dp[i&1][j-1][x][0], bi[j-1][x]));
ans = add(ans, mul(dp[i&1][j-1][x][1], bi[j-1][x-1]));
}
}
else{
ans = add(ans, dp[(i-1)&1][j][k][t]);
if (t == 0 && l[i] <= po[j-1]+1 && po[j]-1 <= r[i])
ans = add(ans, dp[(i-1)&1][j][k-1][0]);
if (t == 1 && l[i] <= po[j] && po[j] <= r[i])
ans = add(ans, dp[(i-1)&1][j][k-1][0]);
}
dp[i&1][j][k][t] = ans;
}
printf("%d\n", add(dp[n&1][m+1][0][0], mod-1));
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:32:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < vec.size(); i++)
~~^~~~~~~~~~~~
boat.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &n);
~~~~~^~~~~~~~~~
boat.cpp:27:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &l[i], &r[i]);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Execution timed out |
2050 ms |
5240 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Execution timed out |
2050 ms |
5240 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
90 ms |
5240 KB |
Output is correct |
| 2 |
Correct |
97 ms |
5240 KB |
Output is correct |
| 3 |
Correct |
107 ms |
5240 KB |
Output is correct |
| 4 |
Correct |
112 ms |
5240 KB |
Output is correct |
| 5 |
Correct |
87 ms |
5240 KB |
Output is correct |
| 6 |
Correct |
96 ms |
5240 KB |
Output is correct |
| 7 |
Correct |
92 ms |
5240 KB |
Output is correct |
| 8 |
Correct |
90 ms |
5240 KB |
Output is correct |
| 9 |
Correct |
97 ms |
5240 KB |
Output is correct |
| 10 |
Correct |
91 ms |
5240 KB |
Output is correct |
| 11 |
Correct |
86 ms |
5240 KB |
Output is correct |
| 12 |
Correct |
88 ms |
5240 KB |
Output is correct |
| 13 |
Correct |
87 ms |
5240 KB |
Output is correct |
| 14 |
Correct |
118 ms |
5240 KB |
Output is correct |
| 15 |
Correct |
121 ms |
5240 KB |
Output is correct |
| 16 |
Correct |
38 ms |
5240 KB |
Output is correct |
| 17 |
Correct |
39 ms |
5240 KB |
Output is correct |
| 18 |
Correct |
39 ms |
5240 KB |
Output is correct |
| 19 |
Correct |
41 ms |
5240 KB |
Output is correct |
| 20 |
Correct |
45 ms |
5240 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Execution timed out |
2050 ms |
5240 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
