飞扬的小鸟

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)

转载于:https://www.cnblogs.com/karryW/p/10692455.html