Submission #1061818

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061818		Andrey	Sequence (APIO23_sequence)	C++17	100 / 100	602 ms	64408 KiB

sequence

#include "sequence.h"
#include<bits/stdc++.h>
using namespace std;

vector<int> haha[500001];
vector<pair<int,int>> seg(2500001);
vector<int> wow(2500001);

void upd(int l, int r, int ql, int qr, int x, int br) {
    if(l == ql && r == qr) {
        wow[x]+=br;
        seg[x] = {seg[x].first+br,seg[x].second+br};
        return;
    }
    int mid = (l+r)/2;
    if(qr <= mid) {
        upd(l,mid,ql,qr,x*2,br);
    }
    else if(ql > mid) {
        upd(mid+1,r,ql,qr,x*2+1,br);
    }
    else {
        upd(l,mid,ql,mid,x*2,br);
        upd(mid+1,r,mid+1,qr,x*2+1,br);
    }
    seg[x] = {max(seg[x*2].first,seg[x*2+1].first)+wow[x],min(seg[x*2].second,seg[x*2+1].second)+wow[x]};
}

pair<int,int> calc(int l, int r, int ql, int qr, int x) {
    if(ql == l && qr == r) {
        return seg[x];
    }
    int mid = (l+r)/2;
    pair<int,int> a,b;
    if(qr <= mid) {
        a = calc(l,mid,ql,qr,x*2);
        return {a.first+wow[x],a.second+wow[x]};
    }
    else if(ql > mid) {
        a = calc(mid+1,r,ql,qr,x*2+1);
        return {a.first+wow[x],a.second+wow[x]};
    }
    else {
        a = calc(l,mid,ql,mid,x*2);
        b = calc(mid+1,r,mid+1,qr,x*2+1);
        return {max(a.first,b.first)+wow[x],min(a.second,b.second)+wow[x]};
    }
}

int sequence(int n, std::vector<int> a) {
    for(int i = 0; i < a.size(); i++) {
        haha[a[i]].push_back(i+1);
    }
    for(int i = 1; i <= n; i++) {
        upd(0,n,i,n,1,-1);
    }
    int ans = 1;
    for(int i = 1; i <= n; i++) {
        for(int v: haha[i]) {
            upd(0,n,v,n,1,1);
        }
        vector<pair<int,int>> big(1,{(int)(-1e9),69});
        vector<pair<int,int>> sm(1,{(int)(1e9),69});
        for(int j = 0; j < haha[i].size(); j++) {
            int p = haha[i][j];
            pair<int,int> c = calc(0,n,p,n,1);
            if(c.second > 0) {
                if(c.second-(big[big.size()-1].first+j+1) <= 0) {
                    int l = 0,r = big.size()-1;
                    while(l < r) {
                        int m = (l+r)/2;
                        if(c.second-(big[m].first+j+1) <= 0) {
                            r = m;
                        }
                        else {
                            l = m+1;
                        }
                    }
                    ans = max(ans,j+1-big[l].second);
                }
            }
            else if(c.first < 0) {
                if(c.first-(sm[sm.size()-1].first-j-1) >= 0) {
                    int l = 0,r = sm.size()-1;
                    while(l < r) {
                        int m = (l+r)/2;
                        if(c.first-(sm[m].first-j-1) >= 0) {
                            r = m;
                        }
                        else {
                            l = m+1;
                        }
                    }
                    ans = max(ans,j+1-sm[l].second);
                }
            }
            else {
                ans = max(ans,j+1);
            }
            c = calc(0,n,0,p,1);
            if(c.first-j > big[big.size()-1].first) {
                big.push_back({c.first-j,j});
            }
            if(c.second+j < sm[sm.size()-1].first) {
                sm.push_back({c.second+j,j});
            }
        }
        for(int v: haha[i]) {
            upd(0,n,v,n,1,1);
        }
    }
    return ans;
}

Compilation message (stderr)

sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:51:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for(int i = 0; i < a.size(); i++) {
      |                    ~~^~~~~~~~~~
sequence.cpp:64:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |         for(int j = 0; j < haha[i].size(); j++) {
      |                        ~~^~~~~~~~~~~~~~~~

• 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