#include <bits/stdc++.h>
using namespace std;
const int MAX = 500 + 5;
const int MOD = 1e9 + 7;
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
int 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 < 2; i++) {
int k = lower_bound(bin.begin(),bin.end(),a[i]) - bin.begin();
int pre = 1;
for (int j = 0; j < k; j++) {pre += ways[j]; pre %= MOD;}
for (; k+1 < bin.size() && bin[k+1] <= b[i]; k++) {
int sz = bin[k+1] - bin[k];
newWays[k] += pre + ways[k] * sz % MOD *(sz-1) % MOD / 2;
newWays[k] %= MOD;
pre += ways[k]*sz;
pre %= MOD;
}
ways = newWays;
}
for (int k = 0; k < bin.size(); 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 'int main()':
boat.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (; k+1 < bin.size() && bin[k+1] <= b[i]; k++) {
~~~~^~~~~~~~~~~~
boat.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int k = 0; k < bin.size(); k++) {ans += ways[k]*(bin[k+1]-bin[k]); ans %= MOD;}
~~^~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
3 ms |
384 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |