Submission #971084

#	Time	Username	Problem	Language	Result	Execution time	Memory
971084		Unforgettablepl	Split the sequence (APIO14_sequence)	C++17	Compilation error	0 ms	0 KiB

sequence

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

#define int long long

struct fraction {
    int n,d;
    fraction(int n,int d):n(n),d(d){}
    bool operator<(const fraction &other) const {
        return __int128(n)*__int128(other.d)<__int128(other.n)*__int128(d);
    }
};

struct line {
    int m,k,idx_1,idx_2;
    line(int m,int k):m(m),k(k),idx_1(idx_1),idx_2(idx_2){}
    int operator()(int x) {
        return m*x+k;
    }
};

fraction getIntersect(line a,line b) {
    return {a.k - b.k,b.m - a.m};
}

void addline(deque<line> &hull, line x) {
    while(hull.size()>1 and getIntersect(hull[hull.size()-2],x)<getIntersect(hull[hull.size()-2],hull.back()))hull.pop_back();
    hull.emplace_back(x);
}

tuple<int,int,int> get(deque<line> &hull, int x){
    while(hull.size()>=2 and hull.front()(x)<=hull[1](x))hull.pop_front();
    return {hull.front()(x),hull.front().idx_1,hull.front().idx_2};
}

int DP[100001][202];
pair<int,int> back[100001][202];
deque<line> hulls[202];
int P[100001];

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,k;
    cin >> n >> k;k++;
    for(int i=1;i<=n;i++)cin>>P[i];
    for(int i=1;i<=n;i++)P[i]+=P[i-1];
    for(int i=0;i<=k;i++)addline(hulls[i],{0,0,0,0});
    for(int i=1;i<=n;i++){
        for(int j=k;j;j--){
            if(j!=1){for(int x=i-1;x;x--){
                if(DP[i][j]<P[i]*P[x]-P[x]*P[x]+DP[x][j-1]){
                    DP[i][j] = P[i]*P[x]-P[x]*P[x]+DP[x][j-1];
                    back[i][j] = {x,j-1};
                }
            }}
            auto [ans,last1,last2] = get(hulls[j-1],P[i]);
            if(DP[i][j] != ans)
            {
                cout << ":DFSAOUIHfaspodi8uhjfg";
            }
            back[i][j] = {last1,last2};
            addline(hulls[j],{P[i],DP[i][j]-P[i]*P[i],i,j});
        }
    }
    cout << DP[n][k] << '\n';
    vector<int> ans;
    auto [curr1,curr2] = back[n][k];
    while(curr1 and curr2){
        ans.emplace_back(curr1);
        auto [c1,c2] = back[curr1][curr2];curr1=c1;curr2=c2;
    }
    for(int&i:ans)cout<<i<<' ';
    cout << '\n';
}

Compilation message (stderr)

sequence.cpp: In constructor 'line::line(long long int, long long int)':
sequence.cpp:16:5: warning: 'line::idx_1' is initialized with itself [-Winit-self]
   16 |     line(int m,int k):m(m),k(k),idx_1(idx_1),idx_2(idx_2){}
      |     ^~~~
sequence.cpp:16:5: warning: 'line::idx_2' is initialized with itself [-Winit-self]
sequence.cpp: In function 'int32_t main()':
sequence.cpp:48:52: error: could not convert '{0, 0, 0, 0}' from '<brace-enclosed initializer list>' to 'line'
   48 |     for(int i=0;i<=k;i++)addline(hulls[i],{0,0,0,0});
      |                                                    ^
      |                                                    |
      |                                                    <brace-enclosed initializer list>
sequence.cpp:63:59: error: could not convert '{P[i], (DP[i][j] - (P[i] * P[i])), i, j}' from '<brace-enclosed initializer list>' to 'line'
   63 |             addline(hulls[j],{P[i],DP[i][j]-P[i]*P[i],i,j});
      |                                                           ^
      |                                                           |
      |                                                           <brace-enclosed initializer list>