BZOJ 1055 玩具取名(区间DP)

很显然的区间DP，定义dp[i][j][k]， 如果dp[i][j][k]=1表示字符串[i,j]可以组成k字符。

# include <cstdio>
# include <cstring>
# include <cstdlib>
# include <iostream>
# include <vector>
# include <queue>
# include <stack>
# include <map>
# include <set>
# include <cmath>
# include <algorithm>
using namespace std;
# define lowbit(x) ((x)&(-x))
# define pi acos(-1.0)
# define eps 1e-9
# define MOD 12345678
# define INF 1000000000
# define mem(a,b) memset(a,b,sizeof(a))
# define FOR(i,a,n) for(int i=a; i<=n; ++i)
# define FO(i,a,n) for(int i=a; i<n; ++i)
# define bug puts("H");
# define lch p<<1,l,mid
# define rch p<<1|1,mid+1,r
# define mp make_pair
# define pb push_back
typedef pair<int,int> PII;
typedef vector<int> VI;
# pragma comment(linker, "/STACK:1024000000,1024000000")
typedef long long LL;
int Scan() {
    int res=0, flag=0;
    char ch;
    if((ch=getchar())==‘-‘) flag=1;
    else if(ch>=‘0‘&&ch<=‘9‘) res=ch-‘0‘;
    while((ch=getchar())>=‘0‘&&ch<=‘9‘)  res=res*10+(ch-‘0‘);
    return flag?-res:res;
}
void Out(int a) {
    if(a<0) {putchar(‘-‘); a=-a;}
    if(a>=10) Out(a/10);
    putchar(a%10+‘0‘);
}
const int N=1005;
//Code begin...

struct To{int a[18][2];}to[5];
int dp[205][205][5], p[30], len, a[5];
char wing[205];

void init(){p[‘W‘-‘A‘]=1; p[‘I‘-‘A‘]=2; p[‘N‘-‘A‘]=3; p[‘G‘-‘A‘]=4; mem(dp,-1);}
void dfs(int l, int r)
{
    if (~dp[l][r][0]) return ;
    if (l==r) {dp[l][r][0]=1; dp[l][r][p[wing[l]-‘A‘]]=1; return ;}
    FO(i,l,r) {
        dfs(l,i); dfs(i+1,r);
        FOR(j,1,4) FOR(k,1,a[j]) {
            int tmp1=to[j].a[k][0], tmp2=to[j].a[k][1];
            if (dp[l][i][tmp1]==1&&dp[i+1][r][tmp2]==1) {dp[l][r][j]=1; break;}
        }
    }
    dp[l][r][0]=1;
    return ;
}
int main ()
{
    char s[5];
    init();
    scanf("%d%d%d%d",a+1,a+2,a+3,a+4);
    FOR(i,1,a[1]) scanf("%s",s), to[1].a[i][0]=p[s[0]-‘A‘], to[1].a[i][1]=p[s[1]-‘A‘];
    FOR(i,1,a[2]) scanf("%s",s), to[2].a[i][0]=p[s[0]-‘A‘], to[2].a[i][1]=p[s[1]-‘A‘];
    FOR(i,1,a[3]) scanf("%s",s), to[3].a[i][0]=p[s[0]-‘A‘], to[3].a[i][1]=p[s[1]-‘A‘];
    FOR(i,1,a[4]) scanf("%s",s), to[4].a[i][0]=p[s[0]-‘A‘], to[4].a[i][1]=p[s[1]-‘A‘];
    scanf("%s",wing+1);
    len=strlen(wing+1);
    dfs(1,len);
    int flag=0;
    if (dp[1][len][1]==1) flag=1, putchar(‘W‘);
    if (dp[1][len][2]==1) flag=1, putchar(‘I‘);
    if (dp[1][len][3]==1) flag=1, putchar(‘N‘);
    if (dp[1][len][4]==1) flag=1, putchar(‘G‘);
    if (!flag) {puts("The name is wrong!"); return 0;}
    putchar(‘\n‘);
    return 0;
}