제출 #248858

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
248858		Autoratch	수열 (APIO14_sequence)	C++14	71 / 100	121 ms	131076 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
 
const int N = 1e5 + 1;
const int K = 201;
 
int n,k;
long long s[N];
pair<long long,int> dp[N][K];
vector<long long> m,b,id;
 
bool bad(int l1,int l2,int l3)
{
    return (double)(b[l2]-b[l3])*(m[l2]-m[l1])<(double)(b[l1]-b[l2])*(m[l3]-m[l2]);
}
 
void add(long long mx,long long bx,long long idx)
{
    if(!m.empty() and m.back()==mx and b.back()==bx) return;
    m.push_back(mx),b.push_back(bx),id.push_back(idx);
    while(m.size()>2 and bad(m.size()-3,m.size()-2,m.size()-1))
        m.erase(m.end()-2),b.erase(b.end()-2),id.erase(id.end()-2);
}
 
int ptr;
 
pair<long long,int> query(long long x)
{
    if(m.empty()) return {0,0};
    if(ptr>=m.size()) ptr = m.size()-1;
    while(ptr<m.size()-1 and m[ptr+1]*x+b[ptr+1]>=m[ptr]*x+b[ptr]) ptr++;
    return {m[ptr]*x+b[ptr],id[ptr]};
}
 
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
 
    cin >> n >> k; 
    for(int i = 1;i <= n;i++) cin >> s[i],s[i]+=s[i-1];
    int now = 1,prev = 0;
    for(int j = 0;j <= k;j++)
    {
        m.clear(),b.clear(),id.clear();
        ptr = 0;
        for(int i = 1;i <= n;i++)
        {
            if(j) dp[i][j] = query(s[i]);
            if(i!=n and !((j-1)>1 and !dp[i][j-1].second) and j-1<i) add(s[i],dp[i][j-1].first-s[i]*s[i],i);
        }
    }
    cout << dp[n][k].first << '\n';
    vector<int> ans;
    int l = k;
    for(int x = dp[n][k].second;x;x = dp[x][--l].second) ans.push_back(x);
    reverse(ans.begin(),ans.end());
    for(int x : ans) cout << x << ' ';
}

컴파일 시 표준 에러 (stderr) 메시지

sequence.cpp: In function 'std::pair<long long int, int> query(long long int)':
sequence.cpp:30:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(ptr>=m.size()) ptr = m.size()-1;
        ~~~^~~~~~~~~~
sequence.cpp:31:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(ptr<m.size()-1 and m[ptr+1]*x+b[ptr+1]>=m[ptr]*x+b[ptr]) ptr++;
           ~~~^~~~~~~~~~~
sequence.cpp: In function 'int main()':
sequence.cpp:41:9: warning: unused variable 'now' [-Wunused-variable]
     int now = 1,prev = 0;
         ^~~
sequence.cpp:41:17: warning: unused variable 'prev' [-Wunused-variable]
     int now = 1,prev = 0;
                 ^~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29