#pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") //#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") #ifdef local #include #else #define dump(...) void(0); #endif #include #include namespace man { constexpr inline void chmax(int &a, const int b) noexcept { if(a < b) { a = b; } } inline std::string yes(const bool b) noexcept { return b ? "Yes" : "No"; } } int main() { std::cin.tie(nullptr) -> sync_with_stdio(false); using namespace std::views; int n, s, b, alt; std::cin >> n >> s >> b; bool ok = true; const int64_t lim = (int64_t) s * b; for(const auto i: iota(0, n)) { int h; std::cin >> h; if(i == 0) { alt = h; continue; } ok &= h - alt <= lim; man::chmax(alt, h); } std::cout << man::yes(ok) << '\n'; }