#include <bits/stdc++.h>
using namespace std;
#define dbg(x) cerr << #x << ": " << x << endl;
const int MOD = 1e9 + 7;
int add(int a, int b) {
int res = a + b;
if (res >= MOD) {
res -= MOD;
}
return res;
}
int mul(long long a, int b) {
return a * b % MOD;
}
const int MAX_N = 500 + 1;
int a[MAX_N];
int b[MAX_N];
vector<int> dp[MAX_N];
struct FenwickTree {
vector<int> tree;
int size;
FenwickTree(int n) {
size = n;
tree.resize(size);
}
void update(int pos, int value) {
for (int i = pos; i < size; i |= i + 1) {
tree[i] = add(tree[i], value);
}
}
int query(int pos) {
int res = 0;
for (int i = pos; i >= 0; i = (i & (i + 1)) - 1) {
res = add(res, tree[i]);
}
return res;
}
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> as = {0};
for (int i = 1; i <= n; ++i) {
cin >> a[i] >> b[i];
for (int j = a[i]; j <= b[i]; ++j) {
as.push_back(j);
}
}
sort(as.begin(), as.end());
as.resize(unique(as.begin(), as.end()) - as.begin());
dp[0].assign(1, 1);
a[0] = -1;
b[0] = -1;
FenwickTree pref(as.size());
pref.update(0, 1);
int ans = 0;
for (int i = 1; i <= n; ++i) {
dp[i].resize(b[i] - a[i] + 1);
int m = dp[i].size();
int pos = lower_bound(as.begin(), as.end(), a[i]) - as.begin();
int pos0 = pos;
for (int j = 0; j < m; ++j) {
int x = a[i] + j;
while (as[pos] < x) ++pos;
dp[i][j] = pref.query(pos - 1);
}
for (int j = 0; j < m; ++j) {
int x = a[i] + j;
while (as[pos0] < x) ++pos0;
pref.update(pos0, dp[i][j]);
ans = add(ans, dp[i][j]);
}
}
cout << ans << '\n';
return 0;
}
/*
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
0 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
0 ms |
340 KB |
Output is correct |
6 |
Correct |
0 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
0 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
340 KB |
Output is correct |
13 |
Correct |
0 ms |
340 KB |
Output is correct |
14 |
Correct |
0 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
340 KB |
Output is correct |
16 |
Correct |
0 ms |
340 KB |
Output is correct |
17 |
Correct |
0 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
340 KB |
Output is correct |
19 |
Correct |
1 ms |
340 KB |
Output is correct |
20 |
Correct |
0 ms |
340 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
0 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
0 ms |
340 KB |
Output is correct |
6 |
Correct |
0 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
0 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
340 KB |
Output is correct |
13 |
Correct |
0 ms |
340 KB |
Output is correct |
14 |
Correct |
0 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
340 KB |
Output is correct |
16 |
Correct |
0 ms |
340 KB |
Output is correct |
17 |
Correct |
0 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
340 KB |
Output is correct |
19 |
Correct |
1 ms |
340 KB |
Output is correct |
20 |
Correct |
0 ms |
340 KB |
Output is correct |
21 |
Correct |
58 ms |
7092 KB |
Output is correct |
22 |
Correct |
56 ms |
7100 KB |
Output is correct |
23 |
Correct |
51 ms |
6756 KB |
Output is correct |
24 |
Correct |
56 ms |
7328 KB |
Output is correct |
25 |
Correct |
60 ms |
7508 KB |
Output is correct |
26 |
Correct |
57 ms |
7736 KB |
Output is correct |
27 |
Correct |
58 ms |
7884 KB |
Output is correct |
28 |
Correct |
59 ms |
7856 KB |
Output is correct |
29 |
Correct |
59 ms |
8040 KB |
Output is correct |
30 |
Correct |
73 ms |
11908 KB |
Output is correct |
31 |
Correct |
96 ms |
11708 KB |
Output is correct |
32 |
Correct |
72 ms |
11968 KB |
Output is correct |
33 |
Correct |
71 ms |
11564 KB |
Output is correct |
34 |
Correct |
75 ms |
11756 KB |
Output is correct |
35 |
Correct |
83 ms |
11160 KB |
Output is correct |
36 |
Correct |
82 ms |
11532 KB |
Output is correct |
37 |
Correct |
84 ms |
11708 KB |
Output is correct |
38 |
Correct |
81 ms |
11320 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
489 ms |
524288 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
0 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
0 ms |
340 KB |
Output is correct |
6 |
Correct |
0 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
0 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
340 KB |
Output is correct |
13 |
Correct |
0 ms |
340 KB |
Output is correct |
14 |
Correct |
0 ms |
340 KB |
Output is correct |
15 |
Correct |
1 ms |
340 KB |
Output is correct |
16 |
Correct |
0 ms |
340 KB |
Output is correct |
17 |
Correct |
0 ms |
340 KB |
Output is correct |
18 |
Correct |
1 ms |
340 KB |
Output is correct |
19 |
Correct |
1 ms |
340 KB |
Output is correct |
20 |
Correct |
0 ms |
340 KB |
Output is correct |
21 |
Correct |
58 ms |
7092 KB |
Output is correct |
22 |
Correct |
56 ms |
7100 KB |
Output is correct |
23 |
Correct |
51 ms |
6756 KB |
Output is correct |
24 |
Correct |
56 ms |
7328 KB |
Output is correct |
25 |
Correct |
60 ms |
7508 KB |
Output is correct |
26 |
Correct |
57 ms |
7736 KB |
Output is correct |
27 |
Correct |
58 ms |
7884 KB |
Output is correct |
28 |
Correct |
59 ms |
7856 KB |
Output is correct |
29 |
Correct |
59 ms |
8040 KB |
Output is correct |
30 |
Correct |
73 ms |
11908 KB |
Output is correct |
31 |
Correct |
96 ms |
11708 KB |
Output is correct |
32 |
Correct |
72 ms |
11968 KB |
Output is correct |
33 |
Correct |
71 ms |
11564 KB |
Output is correct |
34 |
Correct |
75 ms |
11756 KB |
Output is correct |
35 |
Correct |
83 ms |
11160 KB |
Output is correct |
36 |
Correct |
82 ms |
11532 KB |
Output is correct |
37 |
Correct |
84 ms |
11708 KB |
Output is correct |
38 |
Correct |
81 ms |
11320 KB |
Output is correct |
39 |
Runtime error |
489 ms |
524288 KB |
Execution killed with signal 9 |
40 |
Halted |
0 ms |
0 KB |
- |