Submission #1182149

#TimeUsernameProblemLanguageResultExecution timeMemory
1182149cpdreamerSequence (APIO23_sequence)C++20
100 / 100
1732 ms77424 KiB
#include "sequence.h" #include <bits/stdc++.h> using namespace std; typedef long long ll; #define P pair #define F first #define all(v) v.begin(),v.end() #define V vector #define pb push_back #define S second const ll MOD=(ll)1e9+7; struct segtree { private: struct node { int mind, maxd; }; node single(int v) { return {v, v}; } node neutral = {INT_MAX, INT_MIN}; node merge(node a, node b) { return {min(a.mind, b.mind), max(a.maxd, b.maxd)}; } node apply(node a, int v) { return {a.mind + v, a.maxd + v}; } void push(int x, int lx, int rx) { if (rx - lx == 1 || operation[x] == 0) return; int v = operation[x]; query[2 * x + 1] = apply(query[2 * x + 1], v); query[2 * x + 2] = apply(query[2 * x + 2], v); operation[2 * x + 1] += v; operation[2 * x + 2] += v; operation[x] = 0; } public: int size; V<node> query; V<int> operation; void init(int n) { size = 1; while (size < n) size *= 2; query.assign(2 * size, neutral); operation.assign(2 * size, 0); } void build(V<int> &a, int x, int lx, int rx) { if (rx - lx == 1) { if (lx < (int)a.size()) { query[x] = single(a[lx]); } return; } int m = (lx + rx) / 2; build(a, 2 * x + 1, lx, m); build(a, 2 * x + 2, m, rx); query[x] = merge(query[2 * x + 1], query[2 * x + 2]); } void build(V<int> &a) { build(a, 0, 0, size); } void set(int l, int r, int v, int x, int lx, int rx) { push(x, lx, rx); if (lx >= r || rx <= l) return; if (l <= lx && rx <= r) { query[x] = apply(query[x], v); operation[x] += v; return; } int m = (lx + rx) / 2; set(l, r, v, 2 * x + 1, lx, m); set(l, r, v, 2 * x + 2, m, rx); query[x] = merge(query[2 * x + 1], query[2 * x + 2]); } void set(int l, int r, int v) { set(l, r, v, 0, 0, size); } node calc(int l, int r, int x, int lx, int rx) { push(x, lx, rx); if (rx <= l || lx >= r) return neutral; if (l <= lx && rx <= r) return query[x]; int m = (lx + rx) / 2; node a = calc(l, r, 2 * x + 1, lx, m); node b = calc(l, r, 2 * x + 2, m, rx); return merge(a, b); } int mind(int l, int r) { return calc(l, r, 0, 0, size).mind; } int maxd(int l, int r) { return calc(l, r, 0, 0, size).maxd; } }; bool inter(P<int,int>a,P<int,int>b){ if(a.F>b.F) swap(a,b); return a.S>=b.F; } int sequence(int N,V<int>A){ V<int>a(N+1); V<int>occ(N+1); V<V<int>>pos(N+1); set<int>st; for(int i=1;i<=N;i++) { a[i] = A[i - 1]; occ[a[i]]++; pos[a[i]].pb(i); st.insert(a[i]); } V<int>d; for(auto u:st) d.pb(u); V<int>b=a; sort(all(b)); int ans=max(occ[b[(N+1)/2]],occ[b[(N+2)/2]]); V<int>vp(N+1); vp[0]=0; for(int i=1;i<=N;i++){ vp[i]=vp[i-1]+1; } segtree tree; tree.init(N+2); tree.build(vp); for(auto u:d){ V<P<P<int,int>,P<int,int>>>q; int sz=(int)pos[u].size(); for(int i=0;i<sz;i++){ int mnl=tree.mind(0,pos[u][i]+1); int mxl=tree.maxd(0,pos[u][i]+1); int mnr=tree.mind(pos[u][i],N+1); int mxr=tree.maxd(pos[u][i],N+1); q.pb({{mnl,mxl},{mnr,mxr}}); } int l=1,r=N; while(l<=r){ int m=l+(r-l)/2; bool flag=false; for(int i=0;i+m-1<sz;i++){ P<int,int>p1={q[i].F.F,q[i].F.S}; P<int,int>p2={q[i+m-1].S.F,q[i+m-1].S.S}; if(inter(p1,p2)) flag=true; } if(flag){ ans=max(ans,m); l=m+1; } else r=m-1; } for(int i=0;i<sz;i++){ tree.set(pos[u][i],N+1,-2); } q.clear(); for(int i=0;i<sz;i++){ int mnl=tree.mind(0,pos[u][i]+1); int mxl=tree.maxd(0,pos[u][i]+1); int mnr=tree.mind(pos[u][i],N+1); int mxr=tree.maxd(pos[u][i],N+1); q.pb({{mnl,mxl},{mnr,mxr}}); } l=1,r=N; while(l<=r){ int m=l+(r-l)/2; bool flag=false; for(int i=0;i+m-1<sz;i++){ P<int,int>p1={q[i].F.F,q[i].F.S}; P<int,int>p2={q[i+m-1].S.F,q[i+m-1].S.S}; if(inter(p1,p2)) flag=true; } if(flag){ ans=max(ans,m); l=m+1; } else r=m-1; } } return ans; }
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