82 lines
1.5 KiB
C++
82 lines
1.5 KiB
C++
#include <bits/stdc++.h> // {{{
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#include <version>
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#ifdef __cpp_lib_ranges_enumerate
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#include <ranges>
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namespace rv = std::views;
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namespace rs = std::ranges;
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#endif
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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using i16 = int16_t;
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using u16 = uint16_t;
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using i32 = int32_t;
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using u32 = uint32_t;
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using i64 = int64_t;
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using u64 = uint64_t;
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using f64 = double;
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using f128 = long double;
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#if __cplusplus >= 202002L
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template <typename T>
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constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T>
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constexpr T MAX = std::numeric_limits<T>::max();
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#endif
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#ifdef LOCAL
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#define db(...) std::print(__VA_ARGS__)
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#define dbln(...) std::println(__VA_ARGS__)
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#else
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#define db(...)
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#define dbln(...)
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#endif
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// }}}
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void solve() {
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u32 n;
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cin >> n;
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vector<i64> a(n);
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for (auto& e : a) cin >> e;
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vector<bool> dp(n + 1, false);
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dp[0] = true;
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for (i32 i = 1; i <= n; ++i) {
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if (i + a[i - 1] <= n && dp[i - 1]) {
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dp[i + a[i - 1]] = true;
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}
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if (i - a[i - 1] - 1 >= 0 && dp[i - a[i - 1] - 1]) {
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dp[i] = true;
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}
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}
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if (dp.back()) {
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cout << "YES\n";
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} else {
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cout << "NO\n";
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}
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}
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int main() { // {{{
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std::cin.exceptions(std::cin.failbit);
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#ifdef LOCAL
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std::cerr.rdbuf(std::cout.rdbuf());
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std::cout.setf(std::ios::unitbuf);
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std::cerr.setf(std::ios::unitbuf);
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#else
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std::cin.tie(nullptr)->sync_with_stdio(false);
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#endif
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u32 tc = 1;
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std::cin >> tc;
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for (u32 t = 0; t < tc; ++t) {
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solve();
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}
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return 0;
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}
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// }}}
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