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37 lines
704 B (Stored with Git LFS)
C++
37 lines
704 B (Stored with Git LFS)
C++
#include <bits/stdc++.h>
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using namespace std;
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inline int read()
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{
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int x=0,f=1,c=getchar();
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while(c<48) c=='-'&&(f=-1),c=getchar();
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while(c>47) x=x*10+c-'0',c=getchar();
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return x*f;
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}
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const int MAXN = 25000005;
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char s[MAXN],t[MAXN];
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int f[MAXN],n,ans;
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inline void manacher()
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{
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for(int i=1,mr=1,mid=0; i<=n; ++i)
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{
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f[i]=i<mr?min(f[mid+mid-i],mr-i):1;
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while(s[i+f[i]]==s[i-f[i]]) ++f[i];
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if(i+f[i]>mr) mr=i+f[i],mid=i;
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}
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}
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int main(int argc, char const *argv[])
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{
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scanf("%s",t+1); n=strlen(t+1);
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s[0]='/'; s[1]='#';
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for(int i=1; i<=n; ++i)
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s[i<<1]=t[i],s[i<<1|1]='#';
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n=n<<1|1; s[n+1]='\\'; manacher();
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for(int i=1; i<=n; ++i) ans=max(ans,f[i]);
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printf("%d\n", ans-1);
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return 0;
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}
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