Submission #125274

#	Time	Username	Problem	Language	Result	Execution time	Memory
125274		dragonslayerit	Mountains (IOI17_mountains)	C++14	100 / 100	42 ms	28024 KiB

mountains

#include "mountains.h"
#include <vector>
#include <algorithm>
#include <cstdio>

int first[2001][2001];//if i is required
int best[2001][2001];

//Is there a case that breaks the algorithm assuming first=best?
     
int maximum_deevs(std::vector<int> y) {
  for(int i=0;i<y.size();i++){
    first[i][i+1]=1;
    best[i][i+1]=1;
  }
  for(int i=y.size()-1;i>=0;i--){
    int k=i+1;
    for(int j=i+2;j<=y.size();j++){
      first[i][j]=first[i][k]+best[k+1][j];
      best[i][j]=std::max(first[i][j],best[i+1][j]);
      if(1LL*(k-i)*(y[j]-y[i])>=1LL*(j-i)*(y[k]-y[i])){
	k=j;
      }
    }
  }
  return best[0][y.size()];
}

Compilation message (stderr)

mountains.cpp: In function 'int maximum_deevs(std::vector<int>)':
mountains.cpp:12:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<y.size();i++){
               ~^~~~~~~~~
mountains.cpp:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=i+2;j<=y.size();j++){
                   ~^~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30