luoguP1941-

luoguP1941-

20分&50分：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N = 20005;
int n,m,k,x[N],y[N],ans,sum,book[N];
int f[10005][1005];
struct node{
	int p,l,h;
}v[N];
bool flag;
inline int read()
{
	int ans=0,w=1;
	char c=getchar();
	while((c<'0'||c>'9')&&c!='-') c=getchar();
	if(c=='-') { w=-1; c=getchar(); }
	while(c>='0'&&c<='9')
	{ ans=ans*10+c-'0'; c=getchar(); }
	return ans*w;
}
int min(int a,int b)
{ if(a<b) return a; return b; }
int max(int a,int b)
{ if(a>b) return a; return b; }
bool cmp(node a,node b)
{ return a.p<b.p; }
void dfs(int t,int high,int ansp,int sumt)
{
    high=min(high,m);
	if(ansp>ans) return ;
	if(high<=0) return ;
	if(book[t])
	{ if(high>=v[book[t]].h||high<=v[book[t]].l) return ; }
	if(t>=n) { flag=1; ans=min(ans,ansp); return ;}
	if(book[t]) ++sumt;
	sum=max(sum,sumt);
	dfs(t+1,high-y[t],ansp,sumt);
	for(int i=1;i<=3;i++)
	 dfs(t+1,high+i*x[t],ansp+i,sumt);
}
void print(int u)
{
	int sum=0;
	for(int i=0;i<=u;i++)
	if(book[i]) ++sum;
	printf("0\n%d\n",sum);
	return ;
}
void work()
{
	for(int i=1;i<=n;i++)
	 for(int j=0;j<=m;j++)
	  f[i][j]=-1;
	f[0][0]=-1;
	for(int i=1;i<=n;i++)
	{
		bool fg=0;
		int ll,rr;
		if(book[i]) ll=v[book[i]].l+1,rr=v[book[i]].h-1;
		else ll=1,rr=m;
		for(int j=ll;j<=rr;j++)
		{
			if(j==m)
			{
				for(int k=1;k<=m;k++)
				if(f[i-1][k]>=0)
				{
					fg=1;
					if(f[i][j]>=0) f[i][j]=min(f[i][j],f[i-1][k]+(m-k)/x[i-1]+((m-k)%x[i-1]!=0));
					else f[i][j]=f[i-1][k]+(m-k)/x[i-1]+((m-k)%x[i-1]!=0);
				}
				break;
			}
			if(f[i-1][j+y[i-1]]>=0&&j+y[i-1]<=m) f[i][j]=f[i-1][j+y[i-1]],fg=1;
			for(int k=1;k<=j/x[i-1];k++)
			{
				if(f[i-1][j-k*x[i-1]]>=0&&(j-k*x[i-1])>0)
				{
					fg=1;
					if(f[i][j]>=0) f[i][j]=min(f[i][j],f[i-1][j-k*x[i-1]]+k);
					else f[i][j]=f[i-1][j-k*x[i-1]]+k;
				}
			}
		}
		if(!fg) { print(i-1); return ;}
	}
	int t=0;
	while(f[n][t]<0) ++t;
	int anst=f[n][t];
	for(int i=t+1;i<=m;i++)
	if(f[n][i]>=0)
	 anst=min(anst,f[n][i]);
	printf("1\n%d\n",anst);
	return ;
}
int main()
{
	printf("%d\n",sizeof(f)>>20);
	freopen("bird.in","r",stdin);
	freopen("bird.out","w",stdout);
	ans=100005;
	n=read(); m=read(); k=read();
	for(int i=0;i<n;i++)
	 x[i]=read(), y[i]=read();
	for(int i=1;i<=k;i++)
	 v[i].p=read(),v[i].l=read(),v[i].h=read();
	sort(v+1,v+k+1,cmp);
	for(int i=1;i<=k;i++)
	 book[v[i].p]=i;
	if(n<10) { work(); return 0; }
	if(v[1].p==0&&k!=0) //50分 改之前: if(v[1].p==0) 20分
	{//cout<<"*";
		for(int i=v[1].l+1;i<v[1].h;i++)
		 dfs(0,i,0,0);
	}
	else
	{
		for(int i=1;i<=m;i++)
		 dfs(0,i,0,0);
    }
    if(flag) printf("1\n%d\n",ans);
    else printf("0\n%d\n",sum);
    return 0;
}

(考场写法)

80分：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N = 100005;
int inf=2147483647;
int n,m,k,f[10005][1005];//f[i][j] 表示到第i步，j高度至少要跳几步
int x[N],y[N],book[N],anst=inf;
struct node{
	int p,l,h;
}v[N];
inline int read()
{
	int ans=0,w=1;
	char c=getchar();
	while((c<'0'||c>'9')&&c!='-') c=getchar();
	if(c=='-') { w=-1; c=getchar(); }
	while(c>='0'&&c<='9')
	{ ans=ans*10+c-'0'; c=getchar(); }
	return ans*w;
}
int min(int a,int b)
{ if(a<b) return a; return b; }
int max(int a,int b)
{ if(a>b) return a; return b; }
bool cmp(node a,node b)
{ return a.p<b.p; }
void print()
{
	bool flag=0;
	for(int i=1;i<=k;i++)
	{
		flag=0;
		for(int j=1;j<=m;j++)
		 if(f[v[i].p][j]<inf) { flag=1; break;}
		if(!flag) { printf("0\n%d\n",i-1); return ;}
	}
}
int main()
{
	freopen("bird.in","r",stdin);
	freopen("bird.out","w",stdout);
	n=read(); m=read(); k=read();
	for(int i=0;i<n;i++)
	 x[i]=read(),y[i]=read();
	for(int i=1;i<=k;i++)
	 v[i].p=read(),v[i].l=read(),v[i].h=read();
	sort(v+1,v+k+1,cmp);
	for(int i=1;i<=k;i++) book[v[i].p]=i;
	memset(f,0x7f,sizeof(f));
	inf=f[0][0];
	int ll,rr;
	if(book[0]) ll=v[book[1]].l+1,rr=v[book[1]].h-1;
	else ll=1,rr=m;
	for(int i=ll;i<=rr;i++) f[0][i]=0;
	for(int i=1;i<=n;i++)
	{
		if(book[i]) ll=v[book[i]].l+1,rr=v[book[i]].h-1;
		else ll=1,rr=m;
		for(int j=ll;j<=rr;j++)
		{
			if(j==m)
			{
				for(int z=m-x[i-1];z<=m;z++)
				{
					f[i][j]=min(f[i][j],f[i-1][z]+1);
					f[i][j]=min(f[i][j],f[i][z]+1);
				}
			}
			if(j+y[i-1]<=m)
			  f[i][j]=min(f[i][j],f[i-1][j+y[i-1]]);
			if(j-x[i-1]>0)
			  f[i][j]=min(f[i][j],f[i-1][j-x[i-1]]+1),
			  f[i][j]=min(f[i][j],f[i][j-x[i-1]]+1);
		}
	}
	for(int i=1;i<=m;i++)
	 anst=min(anst,f[n][i]);
	if(anst<inf) printf("1\n%d\n",anst);
	else print();
	return 0;
}

(题解思路)