제출 #1175075

#제출 시각아이디문제언어결과실행 시간메모리
117507512345678송신탑 (IOI22_towers)C++17
0 / 100
225 ms8460 KiB
#include "towers.h" #include <bits/stdc++.h> using namespace std; const int nx=1e5+5; int n, vl[nx]; vector<int> h={0}, srt; struct segtree { struct node { int mx, mn, difl, difr; node(int mx=0, int mn=1e9, int difl=0, int difr=0): mx(mx), mn(mn), difl(difl), difr(difr){} } d[4*nx]; node merge(node &l, node &r) { node res; res.mx=max(l.mx, r.mx); res.mn=min(l.mn, r.mn); res.difl=max({l.difl, r.difl, r.mx-l.mn}); res.difr=max({l.difr, r.difr, l.mx-r.mn}); return res; } void build(int l, int r, int i) { if (l==r) return d[i]=node(h[l], h[l]), void(); int md=(l+r)/2; build(l, md, 2*i); build(md+1, r, 2*i+1); d[i]=merge(d[2*i], d[2*i+1]); } int getmax(int l, int r, int i, int ql, int qr) { if (qr<l||r<ql) return 0; if (ql<=l&&r<=qr) return d[i].mx; int md=(l+r)/2; return max(getmax(l, md, 2*i, ql, qr), getmax(md+1, r, 2*i+1, ql, qr)); } int getlessleft(int l, int r, int i, int idx, int vl) { if (idx<l||d[i].mn>=vl) return 0; if (l==r) return d[i].mn<vl?l:0; int md=(l+r)/2; int lvl=getlessleft(md+1, r, 2*i+1, idx, vl); return lvl?lvl:getlessleft(l, md, 2*i, idx, vl); } int getlessright(int l, int r, int i, int idx, int vl) { if (r<idx||d[i].mn>=vl) return 0; if (l==r) return d[i].mn<vl?l:0; int md=(l+r)/2; int rvl=getlessright(l, md, 2*i, idx, vl); return rvl?rvl:getlessright(md+1, r, 2*i+1, idx, vl); } } s; void init(int N, std::vector<int> H) { n=N; for (int i=0; i<n;i ++) h.push_back(H[i]); s.build(1, n, 1); for (int i=1; i<=n; i++) { int cl=s.getlessleft(1, n, 1, i, h[i]), cr=s.getlessright(1, n, 1, i, h[i]), f=0; if (cl&&cl+1==i) f=1; if (cr&&cr-1==i) f=1; if (!f) { if (cl&&cr) vl[i]=min(s.getmax(1, n, 1, cl+1, i-1), s.getmax(1, n, 1, i+1, cr-1)); else if (cr) vl[i]=s.getmax(1, n, 1, i+1, cr-1)-h[i]; else if (cl) vl[i]=s.getmax(1, n, 1, cl+1, i-1)-h[i]; else vl[i]=n; } //cout<<"debug "<<i<<' '<<h[i]<<' '<<cl<<' '<<cr<<' '<<vl[i]<<'\n'; if (vl[i]) srt.push_back(2e9); } sort(srt.begin(), srt.end()); } int max_towers(int L, int R, int D) { return srt.end()-lower_bound(srt.begin(), srt.end(), D); }
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