[Manacher+bit]Palindrome

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 struct node{
 5     ll num;
 6     char ch;
 7 }s[100010];
 8 ll p[110010],sum[110010],bit[110010];
 9 ll t,n,a,k,id,maxlen,tt;
10 ll read(ll i){
11     ll res=0;
12     while(i){
13         res+=bit[i];
14         i-=i&-i;
15     }
16     return res;
17 }
18 void add1(ll i,ll x){
19     while(i<110010){
20         bit[i]+=x;
21         i+=i&-i;
22     }
23 }
24 int main(){
25     scanf("%lld",&t);
26     while(t--){
27         memset(p,0,sizeof p);
28         memset(bit,0,sizeof bit);
29         memset(s,0,sizeof s);
30         memset(sum,0,sizeof sum);
31         scanf("%lld",&n);
32         k=0;
33         for(int i=0;i<n;i++){
34             k++;
35             //cin>>s[k].num>>s[k].ch;
36             scanf("%lld %c",&s[k].num,&s[k].ch);
37             tt=s[k].num;
38             if(s[k].ch==s[k-1].ch){
39                 s[k-1].num+=s[k].num;
40                 k--;
41             }
42             add1(k,tt);
43         }
44         id=0,maxlen=0;
45         s[0].ch=‘*‘,s[k+1].ch=‘#‘;
46         for(int i=1;i<=k;i++){
47             if(p[id]+id>i) p[i]=min(p[2*id-i],p[id]+id-i);
48             else p[i]=1; 
49             while(s[i-p[i]].ch==s[i+p[i]].ch&&s[i-p[i]].num==s[i+p[i]].num)++p[i];
50             if(p[i]+i>p[id]+id) id=i;
51             sum[i]=read(i+p[i]-1)-read(i-p[i]);            
52             if(s[i-p[i]].ch==s[i+p[i]].ch) sum[i]+=2*min(s[i-p[i]].num,s[i+p[i]].num);
53             maxlen=max(maxlen,sum[i]);
54         }
55         printf("%lld\n",maxlen);    
56     }
57     return 0;
58 }