Submission #26505

#	Time	Username	Problem	Language	Result	Execution time	Memory
26505		oneshadab	Split the sequence (APIO14_sequence)	C++14	100 / 100	756 ms	88088 KiB

sequence

#include <bits/stdc++.h>

using namespace std;


#define For(i,N) Forr(i, 0, N)
#define Forr(i,a,b) Fotr(i, a, b, 1)
#define Fotr(i,a,b,c) for(int i=(a);i<(b);i+=(c))
#define FOREACH(it, x) for(__typeof__((x).begin()) it=(x).begin();it!=(x).end();it++)
#define MEM(a,x) memset(a,x,sizeof(a))
#define BCHK(a,x) (((a)>>(x))&1)
#define BSET(a,x) ((a)|(1<<(x)))
#define BCLR(a,x) ((a)&(~(1<<(x))))
#define BTGL(a,x) ((a)^(1<<(x)))
#define FMT(...) (sprintf(CRTBUFF, __VA_ARGS__)?CRTBUFF:0)
#define read() freopen("input.txt","r",stdin)
#define write() freopen("output.txt","w",stdout)
#define cpp_io() {ios_base::sync_with_stdio(false);cin.tie(NULL);}
#define BUFFSIZE 30000
#define INF 1000000000
#define MOD 1000000007
#define MAX 100100
#define pb push_back
#define mkpr make_pair
#define pii pair<int, int>
#define fi first
#define si second
typedef long long ll;

char CRTBUFF[BUFFSIZE];

#define dbg(args...) {cout<<"-->";debugger::call(#args,args);cout<<"\n";}
struct debugger{
    static void call(const char* it){}
    template<typename T, typename ... aT>
    static void call(const char* it, T a, aT... rest){
        string b;
        for(;*it&&*it!=',';++it) if(*it!=' ')b+=*it;
        cout<<b<<"="<<a<<" ";
        call(++it, rest...);
    }
};

/* Template Ends */

struct CHT{
	vector<ll> m, b, id;
	int ptr = 0;
	bool bad(int l1, int l2, int l3) {
		return (b[l3] - b[l1]) * (m[l1] - m[l2]) <= (b[l2] - b[l1]) * (m[l1] - m[l3]);
	}
	void clear() {
		ptr = 0;
		m.clear();
		b.clear();
		id.clear();
	}
	void add(ll _m, ll _b, ll idx) {
		m.push_back(_m);
		b.push_back(_b);
		id.push_back(idx);
		int s = m.size();
		while(s >= 3 && bad(s-3, s-2, s-1)) {
			s--;
			m.erase(m.end()-2);
			b.erase(b.end()-2);
			id.erase(id.end()-2);
		}
	}
	ll f(int i, ll x) { return m[i]*x + b[i]; }

	pair<ll,ll>  query(ll x) {
		if(ptr >= m.size()) ptr = m.size()-1;
		while(ptr < m.size()-1 &&
			f(ptr+1, x) >= f(ptr, x)) ptr++;
		return {f(ptr, x), id[ptr]};
	}
};

ll A[MAX+10], S[MAX+10];
ll dp[2][MAX+10];
int fd[202][MAX+10];

int main()
{
    //read();
    cpp_io();
    //begin
    int n, k;
    while(cin >> n >> k){
        For(i, n) cin >> A[i];
        For(i, n) S[i]=A[i]+(i?S[i-1]:0);
        For(j, n) dp[0][j]=fd[0][j]=0;
        CHT h;
        Forr(i, 1, k+1){
            h.clear();
            h.add(0, 0, 0);
            int x=i&1;
            For(j, n){
                if(j==0){
                    dp[x][j]=0;
                    fd[i][j]=0;
                }
                else{
                    tie(dp[x][j], fd[i][j])=h.query(S[j]);
                }
                h.add(S[j], dp[x^1][j]-S[j]*S[j], j);
            }
        }
        ll ans=dp[k&1][n-1];
        cout << ans << "\n";
        int j=fd[k][n-1];
        for(int i=k-1; i>=0; i--){
            cout << j+1;
            if(i) cout << " ";
            j=fd[i][j];
        }
        cout << "\n";
    }
    return 0;
}

Compilation message (stderr)

sequence.cpp: In member function 'std::pair<long long int, long long int> CHT::query(ll)':
sequence.cpp:73:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(ptr >= m.size()) ptr = m.size()-1;
          ^
sequence.cpp:74:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(ptr < m.size()-1 &&
             ^

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