Submission #140868

# Submission time Handle Problem Language Result Execution time Memory
140868 2019-08-05T21:14:28 Z silxikys Split the sequence (APIO14_sequence) C++14
100 / 100
821 ms 82048 KB
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
typedef long double ld;

const int maxn = 1e5+5, maxk = 205;
int N, K, a[maxn];
ll pre[maxn];
ll dp[2][maxn];
int previous[maxk][maxn];

struct FN
{
    int id;
    ll m, b; //in this case, function is a line
    FN(ll _m, ll _b, int _id) : m(_m), b(_b), id(_id) {}
    ll eval(ll x) const {
        return m*x + b;
    }

    ld intersect(const FN& r) const { //returns x coordinate of intersection
        //assert(m != r.m);
        return (ld)(r.b-b)/(ld)(m-r.m);
    }

    friend bool comp(const FN& l1, const FN& l2, const FN& l) {
    	//order in deque: l1, l2, l
    	//true --> l2 is unnecessary
        /*
        if (l1.m == l2.m || l1.m == l.m || l2.m == l.m) {
            printf("(%d, %d), (%d, %d), (%d, %d)\n",l1.m,l1.b,l2.m,l2.b,l.m,l.b);
            fflush(stdout);
            //cout << l1.m << ' ' << l2.m << ' ' << l.m << endl;
        }
        */
    	ld x1 = l1.intersect(l);
        ld x2 = l1.intersect(l2);
        return x1 <= x2;
    }
};

struct Hull: public deque<FN> //convex hull for maximum
{
    void add(const FN& l) {
        //slopes coming in -1,-2,-3,...so add to front of deque rather than back (querying for maximum)
        //if adding to back, need to change the indices
        while (!empty() && back().m == l.m) {
            //assert(back().b <= l.b);
            pop_back();
        }
        while (size() >= 2 && 
            comp(*next(rbegin()),*rbegin(),l)) {
            pop_back();
        }
        /*
        while (!empty() && back().m == l.m) {
            //assert(back().b <= l.b);
            pop_back();
        }
        */
        push_back(l);
        /*
        cout << "----\n";
        for (auto it = begin(); it != end(); ++it) {
            cout << it->m << ' ' << it->b << '\n';
        }
        */
        /*
        if (size() >= 2) {
            assert(next(rbegin())->m != (*rbegin()).m);
        }
        */
    }

    pair<ll,int> query(ll x) {
        while (size() >= 2 && begin()->eval(x) <= next(begin())->eval(x)) {
            pop_front();
        }
        return {begin()->eval(x),begin()->id};
        /*
        pair<ll,int> best = {0,0};
        //cout << "----\n";
        for (auto it = begin(); it != end(); ++it) {
            best = max(best,{it->eval(x),it->id});
            //cout << it->m << ' ' << it->b << '\n';
            if (next(it) != end()) {
                assert(it->m != next(it)->m);
            }
        }
        return best;
        */
    }
};

int main()
{
    //ios_base::sync_with_stdio(false); cin.tie(NULL);
    cin >> N >> K;
    for (int i = 1; i <= N; i++) {
        cin >> a[i];
        pre[i] = a[i] + pre[i-1];
    }
    for (int k = 1; k <= K; k++) {
        Hull hull;
        for (int i = 1; i <= N; i++) {
            //if (i-1 == 0 || pre[i-1] > pre[i-2] ||
            //    (pre[i-1] == pre[i-2] && 
            //    dp[i-1][k-1] > dp[i-2][k-1])) {

                hull.add(FN(pre[i-1],dp[1-(k&1)][i-1]-pre[i-1]*pre[i-1],i-1));
            //}
            //else cout << "discounted " << (i-1) << ' ' << (k-1) << '\n';
            auto p = hull.query(pre[i]);
            dp[k&1][i] = p.first;
            previous[k][i] = p.second;
            //printf("[%d][%d]: %d\n",i,k,dp[i][k]);
        }
    }
    /*
    for (int k = 1; k <= K; k++) {
        for (auto p: hulls[k-1]) {
            cout << p.m << ' ' << p.b << '\n';
        }
    }
    */
    //output
    cout << dp[K&1][N] << '\n';
    int curr = N;
    int k = K;
    vector<int> ans;
    while (k > 0) {
        curr = previous[k][curr];
        k--;
        ans.push_back(curr);
    }
    reverse(ans.begin(),ans.end());
    for (int i: ans) {
        cout << i << ' ';
    }
    cout << '\n';
}

Compilation message

sequence.cpp: In constructor 'FN::FN(ll, ll, int)':
sequence.cpp:15:11: warning: 'FN::b' will be initialized after [-Wreorder]
     ll m, b; //in this case, function is a line
           ^
sequence.cpp:14:9: warning:   'int FN::id' [-Wreorder]
     int id;
         ^~
sequence.cpp:16:5: warning:   when initialized here [-Wreorder]
     FN(ll _m, ll _b, int _id) : m(_m), b(_b), id(_id) {}
     ^~
# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB contestant found the optimal answer: 108 == 108
2 Correct 2 ms 376 KB contestant found the optimal answer: 999 == 999
3 Correct 2 ms 376 KB contestant found the optimal answer: 0 == 0
4 Correct 2 ms 376 KB contestant found the optimal answer: 1542524 == 1542524
5 Correct 2 ms 376 KB contestant found the optimal answer: 4500000000 == 4500000000
6 Correct 2 ms 380 KB contestant found the optimal answer: 1 == 1
7 Correct 2 ms 376 KB contestant found the optimal answer: 1 == 1
8 Correct 2 ms 376 KB contestant found the optimal answer: 1 == 1
9 Correct 2 ms 376 KB contestant found the optimal answer: 100400096 == 100400096
10 Correct 2 ms 424 KB contestant found the optimal answer: 900320000 == 900320000
11 Correct 2 ms 376 KB contestant found the optimal answer: 3698080248 == 3698080248
12 Correct 2 ms 376 KB contestant found the optimal answer: 3200320000 == 3200320000
13 Correct 2 ms 376 KB contestant found the optimal answer: 140072 == 140072
14 Correct 2 ms 376 KB contestant found the optimal answer: 376041456 == 376041456
15 Correct 2 ms 376 KB contestant found the optimal answer: 805 == 805
16 Correct 2 ms 376 KB contestant found the optimal answer: 900189994 == 900189994
17 Correct 2 ms 376 KB contestant found the optimal answer: 999919994 == 999919994
# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB contestant found the optimal answer: 1093956 == 1093956
2 Correct 2 ms 376 KB contestant found the optimal answer: 302460000 == 302460000
3 Correct 3 ms 632 KB contestant found the optimal answer: 122453454361 == 122453454361
4 Correct 3 ms 376 KB contestant found the optimal answer: 93663683509 == 93663683509
5 Correct 2 ms 376 KB contestant found the optimal answer: 1005304678 == 1005304678
6 Correct 2 ms 376 KB contestant found the optimal answer: 933702 == 933702
7 Correct 2 ms 504 KB contestant found the optimal answer: 25082842857 == 25082842857
8 Correct 2 ms 376 KB contestant found the optimal answer: 687136 == 687136
9 Correct 2 ms 380 KB contestant found the optimal answer: 27295930079 == 27295930079
10 Correct 2 ms 376 KB contestant found the optimal answer: 29000419931 == 29000419931
# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB contestant found the optimal answer: 610590000 == 610590000
2 Correct 7 ms 376 KB contestant found the optimal answer: 311760000 == 311760000
3 Correct 4 ms 1400 KB contestant found the optimal answer: 1989216017013 == 1989216017013
4 Correct 2 ms 376 KB contestant found the optimal answer: 1499437552673 == 1499437552673
5 Correct 4 ms 1144 KB contestant found the optimal answer: 1019625819 == 1019625819
6 Correct 4 ms 1400 KB contestant found the optimal answer: 107630884 == 107630884
7 Correct 4 ms 1528 KB contestant found the optimal answer: 475357671774 == 475357671774
8 Correct 3 ms 504 KB contestant found the optimal answer: 193556962 == 193556962
9 Correct 2 ms 504 KB contestant found the optimal answer: 482389919803 == 482389919803
10 Correct 3 ms 632 KB contestant found the optimal answer: 490686959791 == 490686959791
# Verdict Execution time Memory Grader output
1 Correct 3 ms 356 KB contestant found the optimal answer: 21503404 == 21503404
2 Correct 2 ms 376 KB contestant found the optimal answer: 140412195 == 140412195
3 Correct 9 ms 2040 KB contestant found the optimal answer: 49729674225461 == 49729674225461
4 Correct 2 ms 376 KB contestant found the optimal answer: 37485571387523 == 37485571387523
5 Correct 10 ms 2168 KB contestant found the optimal answer: 679388326 == 679388326
6 Correct 9 ms 1912 KB contestant found the optimal answer: 4699030287 == 4699030287
7 Correct 11 ms 2040 KB contestant found the optimal answer: 12418819758185 == 12418819758185
8 Correct 9 ms 2168 KB contestant found the optimal answer: 31093317350 == 31093317350
9 Correct 4 ms 760 KB contestant found the optimal answer: 12194625429236 == 12194625429236
10 Correct 5 ms 1144 KB contestant found the optimal answer: 12345131038664 == 12345131038664
# Verdict Execution time Memory Grader output
1 Correct 6 ms 888 KB contestant found the optimal answer: 1818678304 == 1818678304
2 Correct 6 ms 928 KB contestant found the optimal answer: 1326260195 == 1326260195
3 Correct 69 ms 9436 KB contestant found the optimal answer: 4973126687469639 == 4973126687469639
4 Correct 8 ms 888 KB contestant found the optimal answer: 3748491676694116 == 3748491676694116
5 Correct 52 ms 6068 KB contestant found the optimal answer: 1085432199 == 1085432199
6 Correct 58 ms 6800 KB contestant found the optimal answer: 514790755404 == 514790755404
7 Correct 65 ms 7288 KB contestant found the optimal answer: 1256105310476641 == 1256105310476641
8 Correct 49 ms 6112 KB contestant found the optimal answer: 3099592898816 == 3099592898816
9 Correct 55 ms 6904 KB contestant found the optimal answer: 1241131419367412 == 1241131419367412
10 Correct 68 ms 8568 KB contestant found the optimal answer: 1243084101967798 == 1243084101967798
# Verdict Execution time Memory Grader output
1 Correct 41 ms 4648 KB contestant found the optimal answer: 19795776960 == 19795776960
2 Correct 41 ms 4796 KB contestant found the optimal answer: 19874432173 == 19874432173
3 Correct 643 ms 82048 KB contestant found the optimal answer: 497313449256899208 == 497313449256899208
4 Correct 59 ms 5376 KB contestant found the optimal answer: 374850090734572421 == 374850090734572421
5 Correct 821 ms 81844 KB contestant found the optimal answer: 36183271951 == 36183271951
6 Correct 563 ms 58188 KB contestant found the optimal answer: 51629847150471 == 51629847150471
7 Correct 627 ms 62376 KB contestant found the optimal answer: 124074747024496432 == 124074747024496432
8 Correct 505 ms 51412 KB contestant found the optimal answer: 309959349080800 == 309959349080800
9 Correct 505 ms 58352 KB contestant found the optimal answer: 124113525649823701 == 124113525649823701
10 Correct 640 ms 74132 KB contestant found the optimal answer: 124309619349406845 == 124309619349406845