cp/codeforces/894/c.cc
2025-03-07 12:52:53 -05:00

131 lines
2.3 KiB
C++

#include <bits/stdc++.h> // {{{
// https://codeforces.com/blog/entry/96344
#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
using namespace std;
template <typename T>
[[nodiscard]] static T MIN() {
return std::numeric_limits<T>::min();
}
template <typename T>
[[nodiscard]] static T MAX() {
return std::numeric_limits<T>::max();
}
template <typename T>
[[nodiscard]] static T sc(auto&& x) {
return static_cast<T>(x);
}
template <typename T>
[[nodiscard]] static T sz(auto&& x) {
return static_cast<T>(x.size());
}
#define prln(...) std::println(__VA_ARGS__)
#define pr(...) std::print(__VA_ARGS__)
#ifdef LOCAL
#define dbgln(...) std::println(__VA_ARGS__)
#define dbg(...) std::print(__VA_ARGS__)
#endif
using ll = long long;
using ld = long double;
template <typename T>
using ve = std::vector<T>;
template <typename T, size_t N>
using ar = std::array<T, N>;
template <typename T1, typename T2>
using pa = std::pair<T1, T2>;
template <typename... Ts>
using tu = std::tuple<Ts...>;
template <typename... Ts>
using dq = std::deque<Ts...>;
template <typename... Ts>
using qu = std::queue<Ts...>;
template <typename... Ts>
using pq = std::priority_queue<Ts...>;
template <typename... Ts>
using st = std::stack<Ts...>;
#define ff first
#define ss second
#define eb emplace_back
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
// }}}
inline static void NO() {
prln("NO");
}
inline static void YES() {
prln("YES");
}
void solve() {
int n;
cin >> n;
ve<int> a(n);
for (auto& e : a)
cin >> e;
ve<int> b(n, 0);
int write = n - 1;
int y = 0;
int i = 0;
while (i < n) {
++y;
while (i + 1 < n && a[i] == a[i + 1]) {
++y;
++i;
}
if ((b[write] = y) != a[write]) {
NO();
return;
};
--write;
if (i + 1 < n) {
for (int j = 0; j < a[i] - a[i + 1] - 1; ++j) {
if ((b[write] = y) != a[write]) {
NO();
return;
}
--write;
}
}
++i;
}
while (write >= 0) {
if ((b[write] = y) != a[write]) {
NO();
return;
}
--write;
}
YES();
}
int main() { // {{{
cin.tie(nullptr)->sync_with_stdio(false);
cin.exceptions(cin.failbit);
int t = 1;
cin >> t;
while (t--) {
solve();
}
return 0;
}
// }}}