#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
ll MOD = 1e9 + 7;
int n, arr[101010];
struct Matrixseg{
struct Matrix {
ll a, b, c, d;
} tree[404040];
Matrix E;
Matrix get_mat(int d) {
if (d == 0) return E;
if (d % 2 == 0) return {d/2 + 1, MOD-1, 1, 0};
else return {d/2 + 1, 0, 1, 0};
}
Matrix mat_pow(Matrix A, int p) {
if (p == 0) return E;
Matrix ret = mat_pow(A, p/2);
ret = prod(ret, ret);
if (p%2 == 0) return ret;
else return prod(ret, A);
}
Matrix prod(Matrix A, Matrix B) {
Matrix ret;
ret.a = (A.a * B.a + A.b * B.c) % MOD;
ret.b = (A.a * B.b + A.b * B.d) % MOD;
ret.c = (A.c * B.a + A.d * B.c) % MOD;
ret.d = (A.c * B.b + A.d * B.d) % MOD;
return ret;
}
void init(int v, int st, int ed) {
if (st == ed) {
tree[v] = E;
return;
}
int mid = (st + ed) / 2;
init(2 * v, st, mid);
init(2 * v + 1, mid + 1, ed);
tree[v] = prod(tree[2 * v + 1], tree[2 * v]);
}
void upd(int v, int st, int ed, int idx, Matrix mat) {
if (st == idx && ed == idx) {
tree[v] = mat;
return;
}
if (st > idx || ed < idx) return;
int mid = (st + ed) / 2;
upd(2 * v, st, mid, idx, mat);
upd(2 * v + 1, mid + 1, ed, idx, mat);
tree[v] = prod(tree[2 * v + 1], tree[2 * v]);
}
Matrix get(int v, int st, int ed, int lt, int rt) {
if (lt <= st && ed <= rt) return tree[v];
if (st > rt || lt > ed) return E;
int mid = (st + ed) / 2;
return prod(get(2 * v + 1, mid + 1, ed, lt, rt), get(2 * v, st, mid, lt, rt));
}
} seg;
set<pii> s;
set<int> nums;
vector<int> vec;
int m;
int get_idx(int val) {
return lower_bound(vec.begin(), vec.end(), val) - vec.begin() + 1;
}
void _modify(set<pii>::iterator it, pii temp) {
auto up = it, dn = it;
seg.upd(1, 1, m, get_idx(it->first), seg.E);
seg.upd(1, 1, m, get_idx(it->second), seg.E);
int bot = 0;
if (it != s.begin()) { dn--; bot = dn->second; }
seg.upd(1, 1, m, get_idx(temp.first), seg.get_mat(temp.first - bot));
if (temp.first != temp.second)
seg.upd(1, 1, m, get_idx(temp.second), seg.mat_pow(seg.get_mat(2), (temp.second - temp.first) / 2));
if (it != s.end()) {
up++;
seg.upd(1, 1, m, get_idx(up->first), seg.get_mat(up->first - temp.second));
}
}
void modify(set<pii>::iterator *it, pii temp) {
if (vec.size() > 0) _modify(*it, temp);
s.erase(*it);
*it = s.insert(temp).first;
nums.insert(temp.first);
nums.insert(temp.second);
}
void _add(pii temp) {
auto up = s.lower_bound(temp), dn = up;
int bot = 0;
if (up != s.begin()) { dn--; bot = dn->second; }
seg.upd(1, 1, m, get_idx(temp.first), seg.get_mat(temp.first - bot));
if (temp.first != temp.second)
seg.upd(1, 1, m, get_idx(temp.second), seg.mat_pow(seg.get_mat(2), (temp.second - temp.first) / 2));
if (up != s.end()) {
seg.upd(1, 1, m, get_idx(up->first), seg.get_mat(up->first - temp.second));
}
}
set<pii>::iterator add(pii temp) {
if (vec.size() > 0) _add(temp);
nums.insert(temp.first);
nums.insert(temp.second);
return s.insert(temp).first;
}
void _rem(set<pii>::iterator it) {
auto up = it, dn = it;
seg.upd(1, 1, m, get_idx(it->first), seg.E);
seg.upd(1, 1, m, get_idx(it->second), seg.E);
int bot = 0;
if (it != s.begin()) { dn--; bot = dn->second; }
if (it != s.end()) {
up++;
seg.upd(1, 1, m, get_idx(up->first), seg.get_mat(up->first - bot));
}
}
set<pii>::iterator rem(set<pii>::iterator it) {
if (vec.size() > 0) _rem(it);
return s.erase(it);
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
seg.E = {1, 0, 0, 1};
ifstream fin("input.txt");
fin >> n;
for (int i = 1; i <= n; i++) fin >> arr[i];
for (int i = 1; i <= n; i++) {
do {
auto up = s.lower_bound({arr[i]+1, 0}), dn = up;
if (up != s.begin()) dn--;
if (up != s.begin() && dn->first <= arr[i] && arr[i] <= dn->second) {
if (dn->first%2 == arr[i]%2) {
int val = dn->second + 1;
if (up != s.end() && val+2 == up->first) modify(&up, {val, up->second});
else up = add({val, val});
val = dn->first-2;
modify(&dn, {dn->first+1, arr[i]-1});
if (dn->first > dn->second) dn = rem(dn);
if (up->first == dn->second+2) {
pii val = {dn->first, up->second};
rem(up);
rem(dn);
add(val);
}
if (dn == s.begin()) {
if (val != -1) {
up = add({max(val, 1), max(val, 1)});
up++;
if (up->first == max(val, 1)+2) {
modify(&up, {max(val, 1), up->second});
up = rem(--up);
}
}
}
else {
dn--;
if (dn->second == val-2) {
modify(&dn, {dn->first, val});
}
else if (dn->second == val-1) {
if (dn->first == dn->second) dn = --rem(dn);
else modify(&dn, {dn->first, dn->second-2});
up = add({val+1, val+1});
up++;
if (up->first == val+3) {
modify(&up, {val+1, up->second});
up = rem(--up);
}
}
else {
add({val, val});
}
}
}
else {
int val = dn->second + 1;
if (up != s.end() && val+2 == up->first) modify(&up, {val, up->second});
else add({val, val});
modify(&dn, {dn->first, arr[i]-1});
}
continue;
}
if (up != s.end() && up->first == arr[i]+1) {
int val = up->second + 1;
up = rem(up);
if (up != s.end() && up->first == val+2) modify(&up, {val, up->second});
else add({val, val});
continue;
}
if (up != s.begin() && dn->second == arr[i]-1) {
modify(&dn, {dn->first, dn->second-2});
if (dn->second < dn->first) dn = --rem(dn);
if (up != s.end() && up->first == arr[i]+2) {
int val = up->second + 1;
up = rem(up);
if (up != s.end() && up->first == val+2) modify(&up, {val, up->second});
else add({val, val});
}
else if (up != s.end() && up->first == arr[i]+3) modify(&up, {arr[i]+1, up->second});
else add({arr[i]+1, arr[i]+1});
continue;
}
if (up != s.begin() && dn->second == arr[i]-2) {
if (up != s.end() && up->first == arr[i]+2) {
pii val = {dn->first, up->second};
rem(up);
rem(dn);
add(val);
}
else modify(&dn, {dn->first, arr[i]});
continue;
}
if (up != s.end() && up->first == arr[i]+2) {
modify(&up, {arr[i], up->second});
continue;
}
add({arr[i], arr[i]});
} while(0);
}
for (auto iter = nums.begin(); iter != nums.end(); iter++) {
vec.push_back(*iter);
}
m = vec.size();
seg.init(1, 1, m);
s.clear();
for (int i = 1; i <= n; i++) {
do {
auto up = s.lower_bound({arr[i]+1, 0}), dn = up;
if (up != s.begin()) dn--;
if (up != s.begin() && dn->first <= arr[i] && arr[i] <= dn->second) {
if (dn->first%2 == arr[i]%2) {
int val = dn->second + 1;
if (up != s.end() && val+2 == up->first) modify(&up, {val, up->second});
else up = add({val, val});
val = dn->first-2;
modify(&dn, {dn->first+1, arr[i]-1});
if (dn->first > dn->second) dn = rem(dn);
if (up->first == dn->second+2) {
pii val = {dn->first, up->second};
rem(up);
rem(dn);
add(val);
}
if (dn == s.begin()) {
if (val != -1) {
up = add({max(val, 1), max(val, 1)});
up++;
if (up->first == max(val, 1)+2) {
modify(&up, {max(val, 1), up->second});
up = rem(--up);
}
}
}
else {
dn--;
if (dn->second == val-2) {
modify(&dn, {dn->first, val});
}
else if (dn->second == val-1) {
if (dn->first == dn->second) dn = --rem(dn);
else modify(&dn, {dn->first, dn->second-2});
up = add({val+1, val+1});
up++;
if (up->first == val+3) {
modify(&up, {val+1, up->second});
up = rem(--up);
}
}
else {
add({val, val});
}
}
}
else {
int val = dn->second + 1;
if (up != s.end() && val+2 == up->first) modify(&up, {val, up->second});
else add({val, val});
modify(&dn, {dn->first, arr[i]-1});
}
continue;
}
if (up != s.end() && up->first == arr[i]+1) {
int val = up->second + 1;
up = rem(up);
if (up != s.end() && up->first == val+2) modify(&up, {val, up->second});
else add({val, val});
continue;
}
if (up != s.begin() && dn->second == arr[i]-1) {
modify(&dn, {dn->first, dn->second-2});
if (dn->second < dn->first) dn = --rem(dn);
if (up != s.end() && up->first == arr[i]+2) {
int val = up->second + 1;
up = rem(up);
if (up != s.end() && up->first == val+2) modify(&up, {val, up->second});
else add({val, val});
}
else if (up != s.end() && up->first == arr[i]+3) modify(&up, {arr[i]+1, up->second});
else add({arr[i]+1, arr[i]+1});
continue;
}
if (up != s.begin() && dn->second == arr[i]-2) {
if (up != s.end() && up->first == arr[i]+2) {
pii val = {dn->first, up->second};
rem(up);
rem(dn);
add(val);
}
else modify(&dn, {dn->first, arr[i]});
continue;
}
if (up != s.end() && up->first == arr[i]+2) {
modify(&up, {arr[i], up->second});
continue;
}
add({arr[i], arr[i]});
} while(0);
Matrixseg::Matrix ans = seg.get(1, 1, m, 1, m);
cout << (ans.a + ans.b) % MOD << "\n";
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
148 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
148 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
135 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
148 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
150 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
148 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
