#include <algorithm>
#include <iostream>
#include <cassert>
#include <vector>
#include <set>
#include <queue>
#define SZ(x) ((int) (x).size())
using namespace std;
typedef long long i64;
const int MOD = (int) 1e9 + 7;
struct Segment {
int l, r;
Segment() = default;
Segment(int _l, int _r):
l(_l), r(_r) {}
};
class DSU {
public:
DSU(int n): f(vector<int>(n)) {
for (int i = 0; i < n; ++i) {
f[i] = i;
}
}
int& operator[](int x) {
int y, p;
for (y = x; y != f[y]; y = f[y]);
for (; x != y; x = p) {
p = f[x];
f[x] = y;
}
return f[y];
}
private:
vector<int> f;
};
int main() {
#ifdef LOCAL_RUN
freopen("task.in", "r", stdin);
freopen("task.out", "w", stdout);
//freopen("task.err", "w", stderr);
#endif // ONLINE_JUDGE
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<Segment> a(n + 1);
vector<int> event(2 * n + 1);
for (int i = 1; i <= n; ++i) {
cin >> a[i].l >> a[i].r;
event[a[i].l] = i;
event[a[i].r] = -i;
}
DSU f(n + 1);
vector<int> before(n + 1, -1), last(n + 1, -1);
for (int i = 1; i <= n; ++i) {
last[i] = i;
}
vector<bool> erased(n + 1, false);
vector<int> stk;
vector<vector<int>> diffGraph(n + 1);
for (int i = 1; i <= 2 * n; ++i) {
if (event[i] > 0) {
int e = event[i];
stk.push_back(e);
} else {
int e = -event[i];
if (before[e] != -1) {
if (!erased[before[e]]) {
cout << "0\n";
return 0;
}
}
int xp = f[e];
if (stk.back() == xp) {
if (e == xp) {
stk.pop_back();
}
} else {
int prev = -1;
while (!stk.empty() && stk.back() != xp) {
int x = stk.back();
stk.pop_back();
if (prev == -1) {
before[last[x]] = -1;
} else {
before[last[x]] = prev;
last[x] = last[prev];
f[prev] = x;
}
prev = x;
}
if (e == xp) {
stk.pop_back();
}
stk.push_back(prev);
diffGraph[prev].push_back(e);
diffGraph[e].push_back(prev);
}
erased[e] = true;
}
}
vector<vector<int>> graph(n + 1);
for (int i = 1; i <= n; ++i) {
for (int to: diffGraph[i]) {
graph[f[i]].push_back(f[to]);
}
}
vector<bool> used(n + 1, false);
vector<int> color(n + 1);
int cnt = 0;
for (int i = 1; i <= n; ++i) {
if (!used[i] && f[i] == i) {
queue<int> q;
q.push(i);
used[i] = true;
color[i] = 0;
while (!q.empty()) {
int node = q.front();
q.pop();
for (int to: graph[node]) {
if (!used[to]) {
used[to] = true;
color[to] = color[node] ^ 1;
q.push(to);
}
}
}
cnt++;
}
}
for (int i = 1; i <= n; ++i) {
if (f[i] != i) continue;
for (int to: graph[i]) {
if (color[i] == color[to]) {
cnt = -1;
}
}
}
if (cnt == -1) {
cout << "0\n";
} else {
int ans = 1;
for (int i = 0; i < cnt; ++i) {
ans = (ans + ans) % MOD;
}
cout << ans << '\n';
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
2184 KB |
Output is correct |
2 |
Correct |
0 ms |
2184 KB |
Output is correct |
3 |
Correct |
0 ms |
2184 KB |
Output is correct |
4 |
Correct |
0 ms |
2184 KB |
Output is correct |
5 |
Correct |
0 ms |
2184 KB |
Output is correct |
6 |
Correct |
0 ms |
2184 KB |
Output is correct |
7 |
Correct |
0 ms |
2184 KB |
Output is correct |
8 |
Correct |
0 ms |
2184 KB |
Output is correct |
9 |
Correct |
0 ms |
2184 KB |
Output is correct |
10 |
Correct |
0 ms |
2184 KB |
Output is correct |
11 |
Correct |
0 ms |
2184 KB |
Output is correct |
12 |
Correct |
0 ms |
2184 KB |
Output is correct |
13 |
Correct |
0 ms |
2184 KB |
Output is correct |
14 |
Correct |
0 ms |
2184 KB |
Output is correct |
15 |
Correct |
0 ms |
2184 KB |
Output is correct |
16 |
Correct |
0 ms |
2184 KB |
Output is correct |
17 |
Correct |
0 ms |
2184 KB |
Output is correct |
18 |
Correct |
0 ms |
2184 KB |
Output is correct |
19 |
Correct |
0 ms |
2184 KB |
Output is correct |
20 |
Correct |
0 ms |
2184 KB |
Output is correct |
21 |
Correct |
0 ms |
2184 KB |
Output is correct |
22 |
Correct |
0 ms |
2184 KB |
Output is correct |
23 |
Correct |
0 ms |
2184 KB |
Output is correct |
24 |
Correct |
0 ms |
2184 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
2184 KB |
Output is correct |
2 |
Correct |
0 ms |
2184 KB |
Output is correct |
3 |
Correct |
0 ms |
2184 KB |
Output is correct |
4 |
Correct |
0 ms |
2184 KB |
Output is correct |
5 |
Correct |
0 ms |
2184 KB |
Output is correct |
6 |
Correct |
0 ms |
2184 KB |
Output is correct |
7 |
Correct |
0 ms |
2184 KB |
Output is correct |
8 |
Correct |
0 ms |
2184 KB |
Output is correct |
9 |
Correct |
0 ms |
2184 KB |
Output is correct |
10 |
Correct |
0 ms |
2184 KB |
Output is correct |
11 |
Correct |
0 ms |
2184 KB |
Output is correct |
12 |
Correct |
0 ms |
2184 KB |
Output is correct |
13 |
Correct |
0 ms |
2184 KB |
Output is correct |
14 |
Correct |
0 ms |
2184 KB |
Output is correct |
15 |
Correct |
0 ms |
2184 KB |
Output is correct |
16 |
Correct |
0 ms |
2184 KB |
Output is correct |
17 |
Correct |
0 ms |
2184 KB |
Output is correct |
18 |
Correct |
0 ms |
2184 KB |
Output is correct |
19 |
Correct |
0 ms |
2184 KB |
Output is correct |
20 |
Correct |
0 ms |
2184 KB |
Output is correct |
21 |
Correct |
0 ms |
2184 KB |
Output is correct |
22 |
Correct |
0 ms |
2184 KB |
Output is correct |
23 |
Correct |
0 ms |
2184 KB |
Output is correct |
24 |
Correct |
0 ms |
2184 KB |
Output is correct |
25 |
Correct |
0 ms |
2452 KB |
Output is correct |
26 |
Correct |
0 ms |
2452 KB |
Output is correct |
27 |
Correct |
0 ms |
2448 KB |
Output is correct |
28 |
Correct |
0 ms |
2452 KB |
Output is correct |
29 |
Correct |
0 ms |
2452 KB |
Output is correct |
30 |
Correct |
0 ms |
2320 KB |
Output is correct |
31 |
Correct |
0 ms |
2448 KB |
Output is correct |
32 |
Correct |
0 ms |
2452 KB |
Output is correct |
33 |
Correct |
0 ms |
2320 KB |
Output is correct |
34 |
Correct |
0 ms |
2320 KB |
Output is correct |
35 |
Correct |
0 ms |
2316 KB |
Output is correct |
36 |
Correct |
0 ms |
2320 KB |
Output is correct |
37 |
Correct |
0 ms |
2320 KB |
Output is correct |
38 |
Correct |
0 ms |
2320 KB |
Output is correct |
39 |
Correct |
0 ms |
2448 KB |
Output is correct |
40 |
Correct |
0 ms |
2320 KB |
Output is correct |
41 |
Correct |
0 ms |
2452 KB |
Output is correct |
42 |
Correct |
0 ms |
2452 KB |
Output is correct |
43 |
Correct |
0 ms |
2448 KB |
Output is correct |
44 |
Correct |
0 ms |
2452 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
2184 KB |
Output is correct |
2 |
Correct |
0 ms |
2184 KB |
Output is correct |
3 |
Correct |
0 ms |
2184 KB |
Output is correct |
4 |
Correct |
0 ms |
2184 KB |
Output is correct |
5 |
Correct |
0 ms |
2184 KB |
Output is correct |
6 |
Correct |
0 ms |
2184 KB |
Output is correct |
7 |
Correct |
0 ms |
2184 KB |
Output is correct |
8 |
Correct |
0 ms |
2184 KB |
Output is correct |
9 |
Correct |
0 ms |
2184 KB |
Output is correct |
10 |
Correct |
0 ms |
2184 KB |
Output is correct |
11 |
Correct |
0 ms |
2184 KB |
Output is correct |
12 |
Correct |
0 ms |
2184 KB |
Output is correct |
13 |
Correct |
0 ms |
2184 KB |
Output is correct |
14 |
Correct |
0 ms |
2184 KB |
Output is correct |
15 |
Correct |
0 ms |
2184 KB |
Output is correct |
16 |
Correct |
0 ms |
2184 KB |
Output is correct |
17 |
Correct |
0 ms |
2184 KB |
Output is correct |
18 |
Correct |
0 ms |
2184 KB |
Output is correct |
19 |
Correct |
0 ms |
2184 KB |
Output is correct |
20 |
Correct |
0 ms |
2184 KB |
Output is correct |
21 |
Correct |
0 ms |
2184 KB |
Output is correct |
22 |
Correct |
0 ms |
2184 KB |
Output is correct |
23 |
Correct |
0 ms |
2184 KB |
Output is correct |
24 |
Correct |
0 ms |
2184 KB |
Output is correct |
25 |
Correct |
0 ms |
2452 KB |
Output is correct |
26 |
Correct |
0 ms |
2452 KB |
Output is correct |
27 |
Correct |
0 ms |
2448 KB |
Output is correct |
28 |
Correct |
0 ms |
2452 KB |
Output is correct |
29 |
Correct |
0 ms |
2452 KB |
Output is correct |
30 |
Correct |
0 ms |
2320 KB |
Output is correct |
31 |
Correct |
0 ms |
2448 KB |
Output is correct |
32 |
Correct |
0 ms |
2452 KB |
Output is correct |
33 |
Correct |
0 ms |
2320 KB |
Output is correct |
34 |
Correct |
0 ms |
2320 KB |
Output is correct |
35 |
Correct |
0 ms |
2316 KB |
Output is correct |
36 |
Correct |
0 ms |
2320 KB |
Output is correct |
37 |
Correct |
0 ms |
2320 KB |
Output is correct |
38 |
Correct |
0 ms |
2320 KB |
Output is correct |
39 |
Correct |
0 ms |
2448 KB |
Output is correct |
40 |
Correct |
0 ms |
2320 KB |
Output is correct |
41 |
Correct |
0 ms |
2452 KB |
Output is correct |
42 |
Correct |
0 ms |
2452 KB |
Output is correct |
43 |
Correct |
0 ms |
2448 KB |
Output is correct |
44 |
Correct |
0 ms |
2452 KB |
Output is correct |
45 |
Correct |
63 ms |
13872 KB |
Output is correct |
46 |
Correct |
59 ms |
13880 KB |
Output is correct |
47 |
Correct |
69 ms |
13872 KB |
Output is correct |
48 |
Correct |
63 ms |
13872 KB |
Output is correct |
49 |
Correct |
66 ms |
13872 KB |
Output is correct |
50 |
Correct |
43 ms |
9024 KB |
Output is correct |
51 |
Correct |
29 ms |
8232 KB |
Output is correct |
52 |
Correct |
56 ms |
10008 KB |
Output is correct |
53 |
Correct |
53 ms |
10568 KB |
Output is correct |
54 |
Correct |
26 ms |
8092 KB |
Output is correct |
55 |
Correct |
23 ms |
7704 KB |
Output is correct |
56 |
Correct |
26 ms |
7704 KB |
Output is correct |
57 |
Correct |
76 ms |
16212 KB |
Output is correct |
58 |
Correct |
59 ms |
10008 KB |
Output is correct |
59 |
Correct |
46 ms |
11248 KB |
Output is correct |
60 |
Correct |
56 ms |
12968 KB |
Output is correct |
61 |
Correct |
63 ms |
13440 KB |
Output is correct |
62 |
Correct |
29 ms |
7796 KB |
Output is correct |
63 |
Correct |
26 ms |
7584 KB |
Output is correct |
64 |
Correct |
33 ms |
8988 KB |
Output is correct |
65 |
Correct |
26 ms |
7704 KB |
Output is correct |
66 |
Correct |
23 ms |
7704 KB |
Output is correct |
67 |
Correct |
43 ms |
14168 KB |
Output is correct |
68 |
Correct |
46 ms |
14048 KB |
Output is correct |
69 |
Correct |
43 ms |
13036 KB |
Output is correct |
70 |
Correct |
43 ms |
13036 KB |
Output is correct |
71 |
Correct |
56 ms |
14312 KB |
Output is correct |
72 |
Correct |
43 ms |
14380 KB |
Output is correct |
73 |
Correct |
36 ms |
13268 KB |
Output is correct |
74 |
Correct |
39 ms |
13204 KB |
Output is correct |
75 |
Correct |
79 ms |
16212 KB |
Output is correct |
76 |
Correct |
76 ms |
16212 KB |
Output is correct |
77 |
Correct |
69 ms |
16212 KB |
Output is correct |
78 |
Correct |
66 ms |
14004 KB |
Output is correct |
79 |
Correct |
66 ms |
13872 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
2184 KB |
Output is correct |
2 |
Correct |
0 ms |
2184 KB |
Output is correct |
3 |
Correct |
0 ms |
2184 KB |
Output is correct |
4 |
Correct |
0 ms |
2184 KB |
Output is correct |
5 |
Correct |
0 ms |
2184 KB |
Output is correct |
6 |
Correct |
0 ms |
2184 KB |
Output is correct |
7 |
Correct |
0 ms |
2184 KB |
Output is correct |
8 |
Correct |
0 ms |
2184 KB |
Output is correct |
9 |
Correct |
0 ms |
2184 KB |
Output is correct |
10 |
Correct |
0 ms |
2184 KB |
Output is correct |
11 |
Correct |
0 ms |
2184 KB |
Output is correct |
12 |
Correct |
0 ms |
2184 KB |
Output is correct |
13 |
Correct |
0 ms |
2184 KB |
Output is correct |
14 |
Correct |
0 ms |
2184 KB |
Output is correct |
15 |
Correct |
0 ms |
2184 KB |
Output is correct |
16 |
Correct |
0 ms |
2184 KB |
Output is correct |
17 |
Correct |
0 ms |
2184 KB |
Output is correct |
18 |
Correct |
0 ms |
2184 KB |
Output is correct |
19 |
Correct |
0 ms |
2184 KB |
Output is correct |
20 |
Correct |
0 ms |
2184 KB |
Output is correct |
21 |
Correct |
0 ms |
2184 KB |
Output is correct |
22 |
Correct |
0 ms |
2184 KB |
Output is correct |
23 |
Correct |
0 ms |
2184 KB |
Output is correct |
24 |
Correct |
0 ms |
2184 KB |
Output is correct |
25 |
Correct |
0 ms |
2452 KB |
Output is correct |
26 |
Correct |
0 ms |
2452 KB |
Output is correct |
27 |
Correct |
0 ms |
2448 KB |
Output is correct |
28 |
Correct |
0 ms |
2452 KB |
Output is correct |
29 |
Correct |
0 ms |
2452 KB |
Output is correct |
30 |
Correct |
0 ms |
2320 KB |
Output is correct |
31 |
Correct |
0 ms |
2448 KB |
Output is correct |
32 |
Correct |
0 ms |
2452 KB |
Output is correct |
33 |
Correct |
0 ms |
2320 KB |
Output is correct |
34 |
Correct |
0 ms |
2320 KB |
Output is correct |
35 |
Correct |
0 ms |
2316 KB |
Output is correct |
36 |
Correct |
0 ms |
2320 KB |
Output is correct |
37 |
Correct |
0 ms |
2320 KB |
Output is correct |
38 |
Correct |
0 ms |
2320 KB |
Output is correct |
39 |
Correct |
0 ms |
2448 KB |
Output is correct |
40 |
Correct |
0 ms |
2320 KB |
Output is correct |
41 |
Correct |
0 ms |
2452 KB |
Output is correct |
42 |
Correct |
0 ms |
2452 KB |
Output is correct |
43 |
Correct |
0 ms |
2448 KB |
Output is correct |
44 |
Correct |
0 ms |
2452 KB |
Output is correct |
45 |
Correct |
63 ms |
13872 KB |
Output is correct |
46 |
Correct |
59 ms |
13880 KB |
Output is correct |
47 |
Correct |
69 ms |
13872 KB |
Output is correct |
48 |
Correct |
63 ms |
13872 KB |
Output is correct |
49 |
Correct |
66 ms |
13872 KB |
Output is correct |
50 |
Correct |
43 ms |
9024 KB |
Output is correct |
51 |
Correct |
29 ms |
8232 KB |
Output is correct |
52 |
Correct |
56 ms |
10008 KB |
Output is correct |
53 |
Correct |
53 ms |
10568 KB |
Output is correct |
54 |
Correct |
26 ms |
8092 KB |
Output is correct |
55 |
Correct |
23 ms |
7704 KB |
Output is correct |
56 |
Correct |
26 ms |
7704 KB |
Output is correct |
57 |
Correct |
76 ms |
16212 KB |
Output is correct |
58 |
Correct |
59 ms |
10008 KB |
Output is correct |
59 |
Correct |
46 ms |
11248 KB |
Output is correct |
60 |
Correct |
56 ms |
12968 KB |
Output is correct |
61 |
Correct |
63 ms |
13440 KB |
Output is correct |
62 |
Correct |
29 ms |
7796 KB |
Output is correct |
63 |
Correct |
26 ms |
7584 KB |
Output is correct |
64 |
Correct |
33 ms |
8988 KB |
Output is correct |
65 |
Correct |
26 ms |
7704 KB |
Output is correct |
66 |
Correct |
23 ms |
7704 KB |
Output is correct |
67 |
Correct |
43 ms |
14168 KB |
Output is correct |
68 |
Correct |
46 ms |
14048 KB |
Output is correct |
69 |
Correct |
43 ms |
13036 KB |
Output is correct |
70 |
Correct |
43 ms |
13036 KB |
Output is correct |
71 |
Correct |
56 ms |
14312 KB |
Output is correct |
72 |
Correct |
43 ms |
14380 KB |
Output is correct |
73 |
Correct |
36 ms |
13268 KB |
Output is correct |
74 |
Correct |
39 ms |
13204 KB |
Output is correct |
75 |
Correct |
79 ms |
16212 KB |
Output is correct |
76 |
Correct |
76 ms |
16212 KB |
Output is correct |
77 |
Correct |
69 ms |
16212 KB |
Output is correct |
78 |
Correct |
66 ms |
14004 KB |
Output is correct |
79 |
Correct |
66 ms |
13872 KB |
Output is correct |
80 |
Correct |
1349 ms |
118912 KB |
Output is correct |
81 |
Correct |
1346 ms |
119088 KB |
Output is correct |
82 |
Correct |
1353 ms |
119096 KB |
Output is correct |
83 |
Correct |
1269 ms |
119012 KB |
Output is correct |
84 |
Correct |
1339 ms |
118892 KB |
Output is correct |
85 |
Correct |
633 ms |
65484 KB |
Output is correct |
86 |
Correct |
489 ms |
60996 KB |
Output is correct |
87 |
Correct |
616 ms |
80484 KB |
Output is correct |
88 |
Correct |
613 ms |
84584 KB |
Output is correct |
89 |
Correct |
443 ms |
59288 KB |
Output is correct |
90 |
Correct |
409 ms |
56216 KB |
Output is correct |
91 |
Correct |
366 ms |
56216 KB |
Output is correct |
92 |
Correct |
1636 ms |
143104 KB |
Output is correct |
93 |
Correct |
566 ms |
80484 KB |
Output is correct |
94 |
Correct |
963 ms |
103504 KB |
Output is correct |
95 |
Correct |
1243 ms |
115036 KB |
Output is correct |
96 |
Correct |
1226 ms |
118120 KB |
Output is correct |
97 |
Correct |
389 ms |
60072 KB |
Output is correct |
98 |
Correct |
399 ms |
61028 KB |
Output is correct |
99 |
Correct |
393 ms |
63248 KB |
Output is correct |
100 |
Correct |
363 ms |
56216 KB |
Output is correct |
101 |
Correct |
399 ms |
56216 KB |
Output is correct |
102 |
Correct |
956 ms |
120024 KB |
Output is correct |
103 |
Correct |
783 ms |
120024 KB |
Output is correct |
104 |
Correct |
593 ms |
108932 KB |
Output is correct |
105 |
Correct |
666 ms |
108932 KB |
Output is correct |
106 |
Correct |
729 ms |
122064 KB |
Output is correct |
107 |
Correct |
789 ms |
122064 KB |
Output is correct |
108 |
Correct |
646 ms |
110972 KB |
Output is correct |
109 |
Correct |
626 ms |
110972 KB |
Output is correct |
110 |
Correct |
1553 ms |
143104 KB |
Output is correct |
111 |
Correct |
1483 ms |
143104 KB |
Output is correct |
112 |
Correct |
1676 ms |
143104 KB |
Output is correct |
113 |
Correct |
1203 ms |
119060 KB |
Output is correct |
114 |
Correct |
1223 ms |
119052 KB |
Output is correct |