noip提高组2014 飞扬的小鸟

DP 用可重复背包优化

代码较长 注意细节

#include<string>
#include<cstring>
#include<cmath>
#include<queue>
#include<iostream>
#include<algorithm>
#include<vector>
#include<cstdio>
#include<cstdlib>
using namespace std;
int shang[10010];
int xia[10010];
int up[10010];
int down[10010];
int f[10010][1010];
int n,m,k;
bool exist[10010];
int main()
{
//freopen("bird.in","r",stdin);
//("bird.out","w",stdout);

int i,j,s,t;

scanf("%d%d%d",&n,&m,&k);

for(i=0;i<n;i++)
{
scanf("%d%d",&shang[i],&xia[i]);
}

for(i=1;i<=n;i++)
{
down[i]=0;
up[i]=m+1;
}

for(i=1;i<=k;i++)
{
scanf("%d%d%d",&j,&s,&t);
down[j]=s;
exist[j]=1;
up[j]=t;
}

for(i=1;i<=n;i++)
{
for(j=0;j<=m;j++)
{
f[i][j]=1000000000;
}
}

f[0][0]=1000000000;

for(i=1;i<=n;i++)
{
for(j=1;j<=m;j++)
{
if(j>=shang[i-1])
{
f[i][j]=min(f[i][j],f[i-1][j-shang[i-1]]+1);
f[i][j]=min(f[i][j],f[i][j-shang[i-1]]+1);
}
if(j==m)
{
for(k=m-shang[i-1];k<=m;k++)
{
f[i][j]=min(f[i-1][k]+1,f[i][j]);
f[i][j]=min(f[i][j],f[i][k]+1);
}
}
}
for(j=1;j<=m;j++)
{
if(j+xia[i-1]<=m)
f[i][j]=min(f[i][j],f[i-1][j+xia[i-1]]);
}
for(j=0;j<=down[i];j++) f[i][j]=1000000000;
for(j=up[i];j<=m;j++) f[i][j]=1000000000;
}
bool hehe=0;
int ans=1000000000;
for(i=down
+1;i<=up
-1;i++)
{
if(f
[i]<ans)
{
hehe=1;
ans=f
[i];
}
}
if(hehe)
{
cout<<"1"<<endl<<ans<<endl;
return 0;
}

for(i=n-1;i>=0;i--)
{
for(j=down[i]+1;j<up[i];j++)
{
if(f[i][j]<1000000000)
{
cout<<"0"<<endl;
k=i;
hehe=1;
break;
}
}
if(hehe) break;
}
int tot=0;
for(i=0;i<=k;i++)
{
if(exist[i]) tot++;
}
cout<<tot;
return 0;
}