bzoj3325 [Scoi2013]密码

Posted 2020-06-20 HugeGun

题目链接

根据回文串的左边、右边不相同，对于每个点把左边的翻过来，为了避免重复更新，记录当前更新到的右端点rr

 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 void inin(int &ret)
27 {
28     ret=0;int f=0;char ch=getchar();
29     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=1;ch=getchar();}
30     while(ch>=‘0‘&&ch<=‘9‘)ret*=10,ret+=ch-‘0‘,ch=getchar();
31     ret=f?-ret:ret;
32 }
33 char s[100010];
34 bool bo[100010][26];
35 int n,a[100010],b[100010];
36 void find(int x)
37 {
38     re(i,0,25)if(!bo[x][i])
39     {
40         s[x]=(char)(‘a‘+i);
41         return ;
42     }
43 }
44 int main()
45 {
46     inin(n);
47     re(i,1,n)inin(a[i]);
48     re(i,1,n-1)inin(b[i]);
49     s[1]=‘a‘;int rr=1;
50     re(i,1,n)
51     {
52         if(s[i]==0)find(i),rr=i;
53         int len=a[i]>>1;
54         int l=i-len-1,r=i+len+1;
55         if(l>0&&r<=n)bo[r][s[l]-‘a‘]=1;
56         while(rr<r-1)rr++,s[rr]=s[2*i-rr];
57         len=b[i]>>1;
58         l=i-len,r=i+len+1;
59         if(l>0&&r<=n)bo[r][s[l]-‘a‘]=1;
60         while(rr<r-1)rr++,s[rr]=s[2*i-rr+1];
61     }
62     re(i,1,n)printf("%c",s[i]);
63      return 0;
64 }