2022/4/3 DP专场总结

#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

#define re register

inline int read(){
	int s=0,f=1;
	char ch=getchar();
	while(!isdigit(ch)){
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(isdigit(ch)){
		s=s*10+int(ch-'0');
		ch=getchar();
	}
	return s*f;
}

const int x=1000;

int n,m;
int p[1005];
int f[2005];

int main(){
	while(n=read()){
		if(!n) return 0;
		for(re int i=1;i<=n;++i)
			p[i]=read();
		sort(p+1,p+n+1);
		m=read();
		memset(f,0,sizeof(f));
		f[m+x]=1;
		int ans=m;
		for(re int i=1;i<=n;++i){
			for(re int j=5;j<=m;++j){
				f[j-p[i]+x]=f[j-p[i]+x]|(1&f[j+x]);
			}
		}
		for(re int i=x-p[n];i<=m+x;++i){
			if(f[i]){
				ans=i-x;
				break;
			}
		}
		printf("%d\n",ans);
	}
	return 0;
}

#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<ios>
using namespace std;

int n,m;
string s;
int v[30][3];
int p[30];
int f[3005][3005];

int main(){
	cin>>n>>m;
	cin>>s;
	char ch;
	for(int i=1;i<=n;++i){
		cin>>ch;
		cin>>v[int(ch-'a')][0]>>v[int(ch-'a')][1];
	}
	for(int i=0;i<=26;++i)
		p[i]=min(v[i][0],v[i][1]);
	memset(f,0x3f,sizeof(f));
	for(int i=0;i<=s.size();++i)
		for(int j=i;j>-1;--j)
			f[i][j]=0;
	for(int l=1;l<=s.size();++l){
		for(int st=1;st+l<=s.size();++st){
			int e=st+l;
			if(st && s[st-1]==s[e-1])
				f[st][e]=min(f[st][e],f[st+1][e-1]);
			f[st][e]=min(f[st][e],f[st+1][e]+p[int(s[st-1]-'a')]);
			f[st][e]=min(f[st][e],f[st][e-1]+p[int(s[e-1]-'a')]);
//			printf("%d %d %d\n",st,e,f[st][e]);
		}
	}
	cout<<f[1][s.size()];
	return 0;
}