Submission #990382

#	Time	Username	Problem	Language	Result	Execution time	Memory
990382		Mihailo	Sequence (APIO23_sequence)	C++17	100 / 100	915 ms	75888 KiB

sequence

#include "sequence.h"
#include <cassert>
#include <cstdio>
#include <bits/stdc++.h>
#define pll pair<long long, long long>
#define mp make_pair
#define pb push_back
#define xx first
#define yy second
typedef long long ll;
using namespace std;

struct node{
    ll zbir;
    ll pref;
    ll suf;
    ll sred;
    node(){}
    node(ll x):zbir(x),pref(x),suf(x),sred(x){}
};

ll n, g, a[500100], m[500100], p1, p2;
node tree[2000100];
vector<ll> app[500100];
vector<pll> v1, v2;

void update(ll i, ll x) {
    i+=g;
    tree[i]=node(x);
    i/=2;
    while(i>0) {
        tree[i].zbir=tree[2*i].zbir+tree[2*i+1].zbir;
        tree[i].pref=max(tree[2*i].pref, tree[2*i].zbir+tree[2*i+1].pref);
        tree[i].suf=max(tree[2*i+1].suf, tree[2*i].suf+tree[2*i+1].zbir);
        tree[i].sred=max(max(tree[2*i].sred, tree[2*i+1].sred), tree[2*i].suf+tree[2*i+1].pref);
        i/=2;
    }
}

ll sum(ll l, ll r) {
    if(l>r) return 0;
    l+=g;
    r+=g;
    ll rez=0;
    while(l<=r) {
        if(l%2) {
            rez+=tree[l].zbir;
            l++;
        }
        if(r%2==0) {
            rez+=tree[r].zbir;
            r--;
        }
        l/=2;
        r/=2;
    }
    return rez;
}

ll prefm(ll l, ll r) {
    if(l>r) return 0;
    l+=g;
    r+=g;
    ll rez=0, trez=0;
    while(l<=r) {
        if(l%2) {
            rez=max(rez, trez+tree[l].pref);
            trez+=tree[l].zbir;
            l++;
        }
        if(r%2==0) {
            rez=max(rez, trez+sum(l-g, r-g-1)+tree[r].pref);
            r--;
        }
        l/=2;
        r/=2;
    }
    return rez;
}

ll sufm(ll l, ll r) {
    if(l>r) return 0;
    l+=g;
    r+=g;
    ll rez=0, trez=0;
    while(l<=r) {
        if(l%2) {
            rez=max(rez, trez+sum(l-g+1, r-g)+tree[l].suf);
            l++;
        }
        if(r%2==0) {
            rez=max(rez, trez+tree[r].suf);
            trez+=tree[r].zbir;
            r--;
        }
        l/=2;
        r/=2;
    }
    return rez;
}

ll solve() {
    g=1;
    while(g<n) g*=2;
    g--;
    for(ll i=1; i<=n; i++) {
        app[a[i]].pb(i);
        m[i]=app[a[i]].size();
    }
    ll rez=0;
    for(ll i=1; i<=n; i++) update(i, 1);
    for(ll i=1; i<=n; i++) {
        if(app[i].empty()) continue;
        for(ll j=0; j<app[i].size(); j++) {
            update(app[i][j], 0);
        }
        if(sum(1, n)<0) return rez;
        for(ll j=0; j<app[i].size(); j++) {
            update(app[i][j], -1);
        }
        for(ll j=0; j<app[i].size(); j++) {
            if(v1.empty()||v1.back().yy<prefm(1, app[i][j]-1)) v1.pb(mp(app[i][j], prefm(1, app[i][j]-1)));
        }
        for(ll j=app[i].size()-1; j>=0; j--) {
            if(v2.empty()||v2.back().yy<sufm(app[i][j]+1, n)) v2.pb(mp(app[i][j], sufm(app[i][j]-1, n)));
        }
        p1=0;
        p2=v2.size()-1;
        while(p2>=0) {
            if(p1>=v1.size()||v1[p1].xx>v2[p2].xx) {
                p2--;
                continue;
            }
            if(v1[p1].yy+v2[p2].yy>=sum(1, n)) {
                rez=max(rez, m[v2[p2].xx]-m[v1[p1].xx]+1);
                p2--;
            }
            else p1++;
        }
        v1.clear();
        v2.clear();
    }
    return rez;
}

int sequence(int N, vector<int> A) {
    ll rez=0;
    n=N;
    for(ll i=0; i<N; i++) a[i+1]=A[i];
    rez=solve();
    for(ll i=1; i<=n; i++) {
        app[i].clear();
    }
    for(ll i=0; i<N; i++) a[i+1]=N+1-A[i];
    rez=max(rez, solve());
    for(ll i=1; i<=n; i++) {
        app[i].clear();
    }
    return rez;
}

Compilation message (stderr)

sequence.cpp: In function 'll solve()':
sequence.cpp:114:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  114 |         for(ll j=0; j<app[i].size(); j++) {
      |                     ~^~~~~~~~~~~~~~
sequence.cpp:118:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |         for(ll j=0; j<app[i].size(); j++) {
      |                     ~^~~~~~~~~~~~~~
sequence.cpp:121:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |         for(ll j=0; j<app[i].size(); j++) {
      |                     ~^~~~~~~~~~~~~~
sequence.cpp:130:18: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  130 |             if(p1>=v1.size()||v1[p1].xx>v2[p2].xx) {
      |                ~~^~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 7 / 7
• Subtask 4: 12 / 12
• Subtask 5: 13 / 13
• Subtask 6: 22 / 22
• Subtask 7: 18 / 18