3555: [Ctsc2014]企鹅QQ 字符串哈希

枚举每一位即可

#include<bits/stdc++.h>
using namespace std;
int n,l,p;
long long f1[30005][205],f2[30005][205],mod=10000000000007,bb=13331,ans,sum,tmp[30005];
char s[30005][205];
int main()
{
	//freopen("xf.in","r",stdin);
	scanf("%d%d%d",&n,&l,&p);
	for(int i=1;i<=n;i++)scanf("%s",s[i]+1);
	for(int i=1;i<=n;i++)
	{
		f1[i][1]=s[i][1];
		for(int j=2;j<=l;j++)f1[i][j]=(f1[i][j-1]*bb+s[i][j])%mod;
		f2[i][l]=s[i][l];
		for(int j=l-1;j>=0;j--)f2[i][j]=(f2[i][j+1]*bb+s[i][j])%mod;
	}
	for(int i=1;i<=l;i++)
	{
		for(int j=1;j<=n;j++)tmp[j]=(f1[j][i-1]*233+f2[j][i+1]*101)%mod;
		sort(tmp+1,tmp+n+1);
		for(int j=1;j<=n;j++)if(tmp[j]==tmp[j-1]){sum++;ans+=sum;}else sum=0;
	}
	printf("%lld
",ans);
	return 0;
}