#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const int MOD = 1e9 + 7;
struct s {
int ans[26];
s() {
for(int i = 0; i < 26; i++) ans[i] = 0;
}
};
struct pairhash {
size_t operator()(pair<int, int> const& p) const noexcept {
return (p.first ^ p.second ^ (p.first + p.second));
}
};
vector<vector<pair<int, int>>> ops;
unordered_map<pair<int, int>, s, pairhash> ma, ma2;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
pair<int, int> pee = {-1, -1};
for(int i = 0; i < 26; i++) {
ma[pee].ans[i] = 1;
}
ops.resize(n);
for(int z = 0; z < m; z++) {
int x, y;
cin >> x >> y;
if(x < y) {
ops[x].push_back({y, 1});
}
else {
ops[y].push_back({x, -1});
}
}
for(int i = 1; i < n; i++) {
for(auto pa : ma) {
s ss;
pair<int, int> p;
tie(p, ss) = pa;
for(auto pp : ops[i]) {
if(pp.second == -1) {
p.first = max(p.first, pp.first);
}
else {
p.second = max(p.second, pp.first);
}
}
if(p.first == i) p.first = -1;
if(p.second == i) p.second = -1;
if(p.first == -1) {
int sum = 0;
for(int i = 25; i >= 0; i--) {
sum += ss.ans[i];
sum %= MOD;
if(i) ma2[pee].ans[i-1] += sum;
if(i) ma2[pee].ans[i-1] %= MOD;
}
}
if(p.second == -1) {
int sum = 0;
for(int i = 0; i < 26; i++) {
sum += ss.ans[i];
sum %= MOD;
if(i != 25) ma2[pee].ans[i+1] += sum;
if(i != 25) ma2[pee].ans[i+1] %= MOD;
}
}
for(int i = 0; i < 26; i++) {
ma2[p].ans[i] += ss.ans[i];
ma2[p].ans[i] %= MOD;
}
}
unordered_map<pair<int, int>, s, pairhash>().swap(ma);
swap(ma, ma2);
}
int sum = 0;
for(auto p : ma) {
for(int i = 0; i < 26; i++) {
sum += p.second.ans[i];
sum %= MOD;
}
}
cout << sum << '\n';
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
468 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
452 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
1 ms |
468 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |