33 lines
616 B
C++
33 lines
616 B
C++
#include<cstdio>
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#include<cstring>
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#include<algorithm>
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using namespace std;
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const int maxn=51000005;
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int n,R[maxn],ans;
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char a[maxn],s[maxn<<1];
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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scanf("%s",a); n=strlen(a);
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s[0]=s[1]='#';
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for(int i=0;i<n;i++) s[i*2+2]=a[i],s[i*2+3]='#';
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n=2*n+2;
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int maxright=0,mid=0;
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for(int i=1;i<n;i++)
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{
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if(i<maxright) R[i]=min(R[mid*2-i],R[mid]+mid-i);
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else R[i]=1;
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while(s[i-R[i]]==s[i+R[i]]) ++R[i];
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if(R[i]+i>maxright) { maxright=R[i]+i; mid=i; }
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}
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ans=1;
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for(int i=0;i<n;i++) ans=max(ans,R[i]-1);
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printf("%d\n",ans);
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return 0;
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}
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/*
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orzro
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*/
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