【BZOJ3555】 [Ctsc2014]企鹅QQ

BZOJ3555 [Ctsc2014]企鹅QQ

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Solution

只需要前缀Hash,然后考虑每一段的贡献就好了!!!

代码实现

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<set>
#include<map>
#include<iostream>
using namespace std;
#define ll long long
#define re register
#define file(a) freopen(a".in","r",stdin);freopen(a".out","w",stdout)
inline int gi()
{
    int f=1,sum=0;char ch=getchar();
    while(ch>'9' || ch<'0'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0' && ch<='9'){sum=(sum<<3)+(sum<<1)+ch-'0';ch=getchar();}
    return f*sum;
}
#define ull unsigned long long
const int N=30010,L=210;
const ull Base=19260817,Base1=19491001,Base2=23333;
ull Hash[N][L],tmp[N],pw[L];
int n,l,S;
ll ans;
char s[N];
void hAsh(int id)
{
    for(int i=1;i<=l;i++)
        Hash[id][i]=Hash[id][i-1]*Base+s[i];
}
ull getHash(int id,int l,int r)
{
    if(l>r)return 0;
    return Hash[id][r]-Hash[id][l-1]*pw[r-l+1];
}
int main()
{
    n=gi();l=gi();S=gi();
    pw[0]=1;
    for(int i=1;i<=l;i++)
        pw[i]=pw[i-1]*Base;
    for(int i=1;i<=n;i++)
    {
        scanf("%s",s+1);
        hAsh(i);
    }
    for(int j=1;j<=l;j++)
    {
        for(int i=1;i<=n;i++)tmp[i]=Hash[i][j-1]*pw[l-j]+getHash(i,j+1,l);
        sort(tmp+1,tmp+n+1);
        int now=1;
        for(int i=2;i<=n;i++)
        {
            if(tmp[i]==tmp[i-1])ans+=now,now++;
            else now=1;
        }
    }
    printf("%lld\n",ans);
    return 0;
}