还是区间DP做起来舒服些
dp[i][j][k]表示i~j前有/没有'W'的最短长度
1 #include<algorithm> 2 #include<iostream> 3 #include<cstdlib> 4 #include<cstring> 5 #include<cstdio> 6 #include<string> 7 #include<cmath> 8 #include<ctime> 9 #include<queue> 10 #include<stack> 11 #include<map> 12 #include<set> 13 #define rre(i,r,l) for(int i=(r);i>=(l);i--) 14 #define re(i,l,r) for(int i=(l);i<=(r);i++) 15 #define Clear(a,b) memset(a,b,sizeof(a)) 16 #define inout(x) printf("%d",(x)) 17 #define douin(x) scanf("%lf",&x) 18 #define strin(x) scanf("%s",(x)) 19 #define LLin(x) scanf("%lld",&x) 20 #define op operator 21 #define CSC main 22 typedef unsigned long long ULL; 23 typedef const int cint; 24 typedef long long LL; 25 using namespace std; 26 cint inf=214748364; 27 void inin(int &ret) 28 { 29 ret=0;int f=0;char ch=getchar(); 30 while(ch<'0'||ch>'9'){if(ch=='-')f=1;ch=getchar();} 31 while(ch>='0'&&ch<='9')ret*=10,ret+=ch-'0',ch=getchar(); 32 ret=f?-ret:ret; 33 } 34 int n,hh[55][55][2]; 35 char s[55]; 36 bool pd(int l,int r) 37 { 38 int len=(r-l+1); 39 if(len%2)return 0; 40 re(i,1,len>>1)if(s[l+i-1]!=s[(len>>1)+i+l-1])return 0; 41 return 1; 42 } 43 int dfs(int l,int r,int bo) 44 { 45 int &ret=hh[l][r][bo]; 46 if(ret!=inf)return ret; 47 ret=r-l+1; 48 if(bo)re(i,l,r-1)ret=min(ret,dfs(l,i,1)+dfs(i+1,r,1)+1); 49 re(i,l,r-1)ret=min(ret,dfs(l,i,bo)+r-i); 50 if(pd(l,r))ret=min(ret,dfs(l,(l+r)>>1,0)+1); 51 return ret; 52 } 53 int main() 54 { 55 strin(s+1); 56 n=strlen(s+1);re(i,1,n)re(j,1,n)re(k,0,1)hh[i][j][k]=inf; 57 printf("%d",dfs(1,n,1)); 58 return 0; 59 }