Submission #50357

#	Time	Username	Problem	Language	Result	Execution time	Memory
50357		duality	Split the sequence (APIO14_sequence)	C++11	100 / 100	973 ms	239704 KiB

sequence

#define DEBUG 0

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

#if DEBUG
// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}

// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
    public:
        template<typename T>
        _Debug& operator,(T val) {
            cout << val << endl;
            return *this;
        }
};
#define debug _Debug(),
#else
#define printLine(l)
#define printLine2(l,c)
#define printVar(n)
#define printArr(a,l)
#define print2dArr(a,r,c)
#define print2dArr2(a,r,c,l)
#define debug
#endif

// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6
#define mp make_pair
#define pb push_back

// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;

// ---------- END OF TEMPLATE ----------

LLI pre[100001];
LLI dp[201][100001];
int parent[201][100001];
struct line { LLI m,b; int i; };
int bad(line a,line b,line c) {
    return (b.b-a.b)*(b.m-c.m) >= (b.b-c.b)*(b.m-a.m);
}
deque<line> H;
int main() {
    int i;
    int n,k;
    scanf("%d %d",&n,&k);
    for (i = 0; i < n; i++) scanf("%lld",&pre[i+1]),pre[i+1] += pre[i];

    int j;
    for (i = 0; i <= n; i++) dp[0][i] = pre[i]*pre[i];
    for (i = 1; i <= k; i++) {
        for (j = 0; j < n; j++) {
            line l = (line){-2*pre[j],pre[j]*pre[j]+dp[i-1][j],j};
            while ((H.size() >= 2) && bad(H[H.size()-2],H.back(),l)) H.pop_back();
            H.pb(l);
            while ((H.size() >= 2) && ((H[0].m*pre[j+1]+H[0].b) >= (H[1].m*pre[j+1]+H[1].b))) H.pop_front();
            dp[i][j+1] = H[0].m*pre[j+1]+H[0].b+pre[j+1]*pre[j+1];
            parent[i][j+1] = H[0].i;
        }
        H.clear();
    }
    printf("%lld\n",(pre[n]*pre[n]-dp[k][n])/2);
    int u = n;
    for (i = k; i >= 1; i--) printf("%d ",parent[i][u]),u = parent[i][u];
    printf("\n");

    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
     ~~~~~^~~~~~~~~~~~~~~
sequence.cpp:70:52: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (i = 0; i < n; i++) scanf("%lld",&pre[i+1]),pre[i+1] += pre[i];
                             ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~

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