#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MAX = 500 + 5;
const int MOD = 1e9 + 7;
const int INV2 = 5e8 + 4;
int N,ans;
vector<int> a(MAX), b(MAX), ways(2*MAX), newWays(2*MAX), bin; //ways[i] = ways of ending between bin[i] and bin[i+1]-1
vector<vector<int>> Z(MAX);
int exp(int a, int e) {
if (e == 0) return 1;
if (e%2 == 1) return a * exp(a,e-1) % MOD;
int temp = exp(a,e/2);
return temp * temp % MOD;
}
int inv(int a) {
return exp(a,MOD-2);
}
int choose(int n, int k) {
int N = 1, D = 1;
for (int i = 0; i < k; i++) {
N *= (n-i);
N %= MOD;
D *= i+1;
D %= MOD;
}
return N * inv(D) % MOD;
}
int calc(int sz, vector<int> z) {
int res = 0;
for (int i = 1; i <= z.size(); i++) {
res += choose(sz+i-1,i) * z[z.size()-i] % MOD;
res %= MOD;
}
return res;
}
main() {
cin >> N;
for (int i = 0; i < N; i++) {
cin >> a[i] >> b[i];
b[i]++;
bin.push_back(a[i]);
bin.push_back(b[i]);
}
sort(bin.begin(),bin.end());
bin.erase(unique(bin.begin(),bin.end()),bin.end());
for (int i = 0; i < N; i++) {
int pre = 1, k = 0;
for (; bin[k] < a[i]; k++) {pre += ways[k]; pre %= MOD;}
for (; k+1 < bin.size() && bin[k+1] <= b[i]; k++) {
int sz = bin[k+1] - bin[k];
Z[k].push_back(pre);
newWays[k] = calc(sz,Z[k]);
pre += ways[k];
pre %= MOD;
}
ways = newWays;
}
for (int k = 0; k < bin.size()-1; k++) {ans += ways[k]*(bin[k+1]-bin[k]); ans %= MOD;}
cout << (ans < 0 ? ans + MOD : ans) << "\n";
return 0;
}
Compilation message
boat.cpp: In function 'long long int calc(long long int, std::vector<long long int>)':
boat.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 1; i <= z.size(); i++) {
~~^~~~~~~~~~~
boat.cpp: At global scope:
boat.cpp:46:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
main() {
^
boat.cpp: In function 'int main()':
boat.cpp:63:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (; k+1 < bin.size() && bin[k+1] <= b[i]; k++) {
~~~~^~~~~~~~~~~~
boat.cpp:73:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int k = 0; k < bin.size()-1; k++) {ans += ways[k]*(bin[k+1]-bin[k]); ans %= MOD;}
~~^~~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
5 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
4 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
4 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
4 ms |
384 KB |
Output is correct |
| 11 |
Correct |
5 ms |
384 KB |
Output is correct |
| 12 |
Correct |
4 ms |
384 KB |
Output is correct |
| 13 |
Correct |
5 ms |
384 KB |
Output is correct |
| 14 |
Correct |
7 ms |
384 KB |
Output is correct |
| 15 |
Correct |
6 ms |
384 KB |
Output is correct |
| 16 |
Correct |
4 ms |
384 KB |
Output is correct |
| 17 |
Correct |
6 ms |
384 KB |
Output is correct |
| 18 |
Correct |
4 ms |
384 KB |
Output is correct |
| 19 |
Correct |
5 ms |
384 KB |
Output is correct |
| 20 |
Correct |
4 ms |
384 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
5 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
4 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
4 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
4 ms |
384 KB |
Output is correct |
| 11 |
Correct |
5 ms |
384 KB |
Output is correct |
| 12 |
Correct |
4 ms |
384 KB |
Output is correct |
| 13 |
Correct |
5 ms |
384 KB |
Output is correct |
| 14 |
Correct |
7 ms |
384 KB |
Output is correct |
| 15 |
Correct |
6 ms |
384 KB |
Output is correct |
| 16 |
Correct |
4 ms |
384 KB |
Output is correct |
| 17 |
Correct |
6 ms |
384 KB |
Output is correct |
| 18 |
Correct |
4 ms |
384 KB |
Output is correct |
| 19 |
Correct |
5 ms |
384 KB |
Output is correct |
| 20 |
Correct |
4 ms |
384 KB |
Output is correct |
| 21 |
Runtime error |
3 ms |
640 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 22 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
55 ms |
476 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
5 ms |
384 KB |
Output is correct |
| 3 |
Correct |
5 ms |
384 KB |
Output is correct |
| 4 |
Correct |
4 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
4 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
4 ms |
384 KB |
Output is correct |
| 11 |
Correct |
5 ms |
384 KB |
Output is correct |
| 12 |
Correct |
4 ms |
384 KB |
Output is correct |
| 13 |
Correct |
5 ms |
384 KB |
Output is correct |
| 14 |
Correct |
7 ms |
384 KB |
Output is correct |
| 15 |
Correct |
6 ms |
384 KB |
Output is correct |
| 16 |
Correct |
4 ms |
384 KB |
Output is correct |
| 17 |
Correct |
6 ms |
384 KB |
Output is correct |
| 18 |
Correct |
4 ms |
384 KB |
Output is correct |
| 19 |
Correct |
5 ms |
384 KB |
Output is correct |
| 20 |
Correct |
4 ms |
384 KB |
Output is correct |
| 21 |
Runtime error |
3 ms |
640 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 22 |
Halted |
0 ms |
0 KB |
- |
