Submission #742391

#	Time	Username	Problem	Language	Result	Execution time	Memory
742391		jamezzz	Tortoise (CEOI21_tortoise)	C++17	0 / 100	1 ms	980 KiB

tortoise

#include <bits/stdc++.h>
using namespace std;
 
#define sf scanf
#define pf printf
#define pb push_back
#define INF 1023456789
 
#define maxn 305
 
int n,a[maxn],pv[maxn],nx[maxn];
vector<int> shop,play;
int memo[2*maxn][maxn];
 
int dp(int t,int i){
	if(i>shop.size()||t>2*n)return 0;
	if(memo[t][i]!=-1)return memo[t][i];
	int num=0;
	int sd=INF;
	if(pv[i]!=-1)sd=min(sd,shop[i]-play[pv[i]]);
	if(nx[i]<play.size())sd=min(sd,play[nx[i]]-shop[i]);
	int cur=t,ans=0;
	for(int x=0;x<=a[shop[i]];++x){
		//back and forth x-1 times, then get 1 and go to another shop
		if(cur>2*shop[i])break;
		for(int y=i;y<=i+1;++y){
			int take=INF;
			if(x==0)take=min(take,abs(shop[y]-shop[i]));
			if(pv[i]!=-1)take=min(take,abs(shop[y]-play[pv[i]])+abs(shop[i]-play[pv[i]]));
			if(nx[i]<play.size())take=min(take,abs(shop[y]-play[nx[i]])+abs(shop[i]-play[nx[i]]));
			if(y!=i)ans=max(ans,dp(cur+take,y)+x);
			else ans=max(ans,x);
		}
		if(x>0)cur+=2*sd;
	}
	//pf("dp %d %d: %d\n",t,i,ans);
	return memo[t][i]=ans;
}
 
int main(){
	sf("%d",&n);
	int sm=0;
	for(int i=0;i<n;++i){
		sf("%d",&a[i]);
		if(a[i]==-1)play.pb(i);
		else shop.pb(i),sm+=a[i];
	}
	if(shop.size()==0){
		pf("0\n");
		return 0;
	}
	int cur=-1;
	for(int x=0;x<shop.size();++x){
		int i=shop[x];
		while(cur+1<play.size()&&play[cur+1]<i)++cur;
		pv[x]=cur;
		nx[x]=cur+1;
	}
	memset(memo,-1,sizeof memo);
	pf("%d\n",sm-dp(shop[0],0));
}

Compilation message (stderr)

tortoise.cpp: In function 'int dp(int, int)':
tortoise.cpp:16:6: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |  if(i>shop.size()||t>2*n)return 0;
      |     ~^~~~~~~~~~~~
tortoise.cpp:21:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  if(nx[i]<play.size())sd=min(sd,play[nx[i]]-shop[i]);
      |     ~~~~~^~~~~~~~~~~~
tortoise.cpp:30:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |    if(nx[i]<play.size())take=min(take,abs(shop[y]-play[nx[i]])+abs(shop[i]-play[nx[i]]));
      |       ~~~~~^~~~~~~~~~~~
tortoise.cpp:18:6: warning: unused variable 'num' [-Wunused-variable]
   18 |  int num=0;
      |      ^~~
tortoise.cpp: In function 'int main()':
tortoise.cpp:53:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |  for(int x=0;x<shop.size();++x){
      |              ~^~~~~~~~~~~~
tortoise.cpp:55:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |   while(cur+1<play.size()&&play[cur+1]<i)++cur;
      |         ~~~~~^~~~~~~~~~~~
tortoise.cpp:41:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |  sf("%d",&n);
      |    ^
tortoise.cpp:44:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |   sf("%d",&a[i]);
      |     ^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 25
• Subtask 5: 0 / 27