Submission #239597

#	Time	Username	Problem	Language	Result	Execution time	Memory
239597		m3r8	Aliens (IOI16_aliens)	C++14	12 / 100	17 ms	7040 KiB

aliens

#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <vector>
#include <utility>
#include "aliens.h"


#define N 100100
#define M 1001000
#define ll long long
#define ii std::pair<int,int>

ll over[N];
int line[M];
std::vector<ii> pt;
std::vector<std::vector<ll>> dp;

ll minl(ll a, ll b){
  if(a == -1)return b;  
  if(b == -1)return a;
  return a < b ? a:b;
};

void solvedc(int kl, int kr, int l, int r, int j){
  if(kl >= kr)return;
  if(l > kl)return;
  if(l >= r)return;
  ll infl;
  if(l == r-1){
    for(int i = kl;i<kr;i++){
      if(over[i]){
        infl = std::max(over[i] - 1,0ll) + (pt[i].first-pt[l].first+1);   
      }else{
        infl = std::max(over[i-1]-1,0ll) + (pt[i-1].first-pt[l].first+1);  
      };
      dp[i][j] = dp[l][j-1] + infl * infl - over[l] * over[l];   
      //printf("dc: %d %d %d %d %lld %d %d\n",j,i,l,r,dp[i][j],kl,kr);
    };
  }else{
    int km = (kl+kr)>>1;
    int bstId;
    int rr = std::min(r,km);
    ll bst = -1;
    if(over[km]){
      infl = std::max(over[km]-1,0ll) + pt[km].first+1;  
    }else{
      infl = std::max(over[km - 1]-1,0ll) + pt[km-1].first+1;  
    };
    ll tmp;
    for(int i = l;i<rr;i++){
      tmp = infl - pt[i].first;
      if(dp[i][j-1] != -1){
        if(dp[i][j-1] + tmp * tmp - over[i] * over[i] <= bst || bst == -1){
          bst = dp[i][j-1] + tmp * tmp - over[i] * over[i];  
          bstId = i;
        };
      };
    };
    //printf("dc: %d %d %d %d %lld %d %d %d\n",j,km,l,r,bst,kl,kr,bstId);
    dp[km][j] = bst;
    solvedc(kl,km,l,bstId+1,j);
    solvedc(km+1,kr,bstId,r,j);
  };
};

ll take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c){
  memset(over,0,sizeof(over));
  memset(line,0,sizeof(line));
  pt.clear();

  dp = std::vector<std::vector<ll>>(n+10,std::vector<ll>(k+10,-1));
  for(int i = 0;i<n;i++){
    if(r[i] >= c[i]){
      line[c[i]] = std::max(line[c[i]],r[i]-c[i]+1);
    }else if(r[i] < c[i]){
      line[r[i]] = std::max(line[r[i]],c[i]-r[i]+1);  
    };
  };

  for(int i = 0;i<m;i++){
    if(line[i])pt.push_back(ii(i,line[i]));  
  };

  for(int i = 1;i<pt.size();i++){
    if(over[i-1] > pt[i-1].second){
      over[i] = over[i-1] + pt[i-1].first - pt[i].first;  
    }else{
      over[i] = pt[i-1].second + pt[i-1].first - pt[i].first;
    };
    if(over[i] < 0)over[i] = 0;
    //printf("pt: %d %d %d\n",pt[i].first,pt[i].second,over[i]);
  };
  over[pt.size()] = 0;
  pt.push_back({0,0});

  //printf("%d %d %d %d\n",pt.size(),pt[0].first,pt[0].second,over[0]);
  for(int i = 0;i<=k;i++)dp[0][i] = 0;
  for(int j = 1;j<=k;j++){
      solvedc(1,pt.size(),0,pt.size()-1,j);
  };
  ll mn = -1;
  for(int i = 1;i<=k;i++){
    //printf("%lld\n",dp[pt.size()-1][i]);
    mn = minl(mn,dp[pt.size()-1][i]);  
  };
  return mn;
};

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:85:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 1;i<pt.size();i++){
                 ~^~~~~~~~~~
aliens.cpp: In function 'void solvedc(int, int, int, int, int)':
aliens.cpp:62:12: warning: 'bstId' may be used uninitialized in this function [-Wmaybe-uninitialized]
     solvedc(kl,km,l,bstId+1,j);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 12 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40