Submission #31433

#	Time	Username	Problem	Language	Result	Execution time	Memory
31433		gs14004	Split the sequence (APIO14_sequence)	C++14	100 / 100	436 ms	86396 KiB

sequence

#include <bits/stdc++.h>
 
using namespace std;
typedef long long lint;
typedef pair<lint, int> pi;
 
struct cht{
    int s,e;
    lint la[100005],lb[100005];
    int label[100005];
    void insert(lint p, lint q, int piv){
        la[e] = p;
        lb[e] = q;
        label[e] = piv;
        while(s+1<e && (lb[e-1] - lb[e-2]) * (la[e] - la[e-1]) <= (la[e-2] - la[e-1])* (lb[e-1] - lb[e])){
            la[e-1] = la[e];
            lb[e-1] = lb[e];
            label[e-1] = label[e];
            e--;
        }
        e++;
    }
    pi query(lint x){
        while(s+1<e && lb[s+1] - lb[s] >= x * (la[s] - la[s+1])) s++;
        return pi(la[s]*x+lb[s],label[s]);
    }
    void clear(){s = e = 0;}
}convexHull;
 
int n,k;
lint dp[2][100005],a[100005];
int track[205][100005];
 
int main(){
    int t;
    scanf("%d %d",&n,&k);
    for (int i=0; i<n; i++) {
        scanf("%d",&t);
        a[i+1] = a[i] + t;
    }
  vector<lint> v;
    for (int t=0; t<=k; t++) {
        convexHull.clear();
        convexHull.insert(0,0,0);
        for (int i=1; i<=n; i++) {
            pi x = convexHull.query(a[i]);
            track[t][i] = x.second;
            dp[t%2][i] = x.first + a[i] * (a[n] - a[i]);
            convexHull.insert(a[i],dp[!(t%2)][i]-a[n]*a[i], i);
        }
      v.push_back(dp[t%2][n]);
    }
  for(int i=2; i<v.size(); i++){
    assert(v[i-1] - v[i-2] >= v[i] - v[i-1]);
  }
    printf("%lld\n",dp[k%2][n]);
    vector<int> res;
    int pos2 = n;
    for(int pos1 = k; pos1; pos1--){
        res.push_back(track[pos1][pos2]);
        pos2 = track[pos1][pos2];
    }
    while (!res.empty()) {
        printf("%d ",res.back());
        res.pop_back();
    }
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:53:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=2; i<v.size(); i++){
                 ^
sequence.cpp:36:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
                         ^
sequence.cpp:38:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&t);
                       ^

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