Submission #1056267

#TimeUsernameProblemLanguageResultExecution timeMemory
1056267ForestedRadio Towers (IOI22_towers)C++17
37 / 100
4045 ms7860 KiB
#include <bits/stdc++.h> using namespace std; using i32 = int; using i64 = long long; template <typename T> using V = vector<T>; template <typename T> using VV = V<V<T>>; template <typename T> using VVV = V<V<V<T>>>; template <typename T> bool chmin(T &x, const T &y) { if (x > y) { x = y; return true; } return false; } template <typename T> bool chmax(T &x, const T &y) { if (x < y) { x = y; return true; } return false; } #define OVERRIDE4(a, b, c, d, ...) d #define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i) #define REP3(i, l, r) for (i32 i = (i32)(l); i < (i32)(r); ++i) #define REP(...) OVERRIDE4(__VA_ARGS__, REP3, REP2)(__VA_ARGS__) #define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i) #define PER3(i, l, r) for (i32 i = (i32)(r)-1; i >= (i32)(l); --i) #define PER(...) OVERRIDE4(__VA_ARGS__, PER3, PER2)(__VA_ARGS__) #define ALL(x) begin(x), end(x) #define LEN(x) (i32) size(x) void dbg(i32 x) { cerr << x; } void dbg(i64 x) { cerr << x; } template <typename T, typename U> void dbg(pair<T, U> p) { cerr << '(' << p.first << ", " << p.second << ')'; } template <typename T> void dbg(V<T> arr) { cerr << '['; REP(i, LEN(arr)) { if (i) { cerr << ", "; } dbg(arr[i]); } cerr << ']'; } void debug() { cerr << '\n'; } template <typename Head, typename... Tail> void debug(Head head, Tail... tail) { dbg(head); cerr << ", "; debug(tail...); } #ifdef DEBUGF #define DBG(...) \ do { \ cerr << #__VA_ARGS__ << " : "; \ debug(__VA_ARGS__); \ } while (false) #else #define DBG(...) (void)0 #endif #include "towers.h" constexpr i32 INF = 1001001001; template <typename T> i32 lob(const V<T> &arr, T v) { return (i32)(lower_bound(ALL(arr), v) - begin(arr)); } template <typename T> i32 upb(const V<T> &arr, T v) { return (i32)(upper_bound(ALL(arr), v) - begin(arr)); } struct RMQ { i32 n; V<i32> dat; RMQ(i32 n) : n(n), dat(2 * n, -INF) {} void update(i32 idx, i32 val) { idx += n; dat[idx] = val; while ((idx /= 2) >= 1) { dat[idx] = max(dat[2 * idx], dat[2 * idx + 1]); } } i32 rmq(i32 l, i32 r) const { l += n; r += n; i32 m = -INF; while (l < r) { if (l & 1) { chmax(m, dat[l++]); } if (r & 1) { chmax(m, dat[--r]); } l /= 2; r /= 2; } return m; } void trc() const { V<i32> arr(n + ALL(dat)); DBG(arr); } }; i32 n; V<i32> h; V<i32> psum; void init(i32 _n, V<i32> _h) { n = _n; h = _h; psum.resize(n + 1, 0); REP(i, n) { psum[i + 1] = psum[i] + (0 < i && i < n - 1 && h[i - 1] < h[i] && h[i] > h[i + 1]); } } i32 max_towers(i32 l, i32 r, i32 delta) { ++r; if (r - l == 1) { return 1; } if (delta == 1) { i32 ans = psum[r - 1] - psum[l + 1] + 1; return ans; } V<i32> g(begin(h) + l, begin(h) + r); i32 m = r - l; V<i32> hs; hs.reserve(3 * m); REP(i, m) { hs.push_back(g[i] - delta); hs.push_back(g[i]); hs.push_back(g[i] + delta); } sort(ALL(hs)); hs.erase(unique(ALL(hs)), end(hs)); i32 k = LEN(hs); RMQ down(k); RMQ up(k); REP(i, m) { i32 d = max(1, up.rmq(lob(hs, g[i] + delta), k) + 1); i32 u = down.rmq(0, lob(hs, g[i] - delta) + 1); i32 idx = lob(hs, g[i]); down.update(idx, d); up.update(idx, u); } i32 ans = down.rmq(0, k); return ans; }
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