hdu 5510

题意：给出n个字符串s[1]..s[n]，问是否存在一个i使得s[j](1<=j<i）不是s[i]的子串，求最大i

思路：KMP+暴力

#include<bits/stdc++.h>
using namespace std;
const int N=503;
const int M=2003;

char s[N][M];
bool vis[N];
int Next[N][M];
int len[N];
int n;
int ans;

void getNext(int x){
    int j, k;
    j = 0; k = -1; Next[x][0] = -1;
    while(j < len[x])
        if(k == -1 || s[x][j] == s[x][k])
            Next[x][++j] = ++k;
        else
            k = Next[x][k];
}

int hh(int x,int y)//x是子串,y是母串
{
    int i = 0, j = 0;
    while(i < len[y] && j < len[x])
    {
        if(j == -1 || s[y][i] == s[x][j])
        {
            i++; j++;
        }
        else
            j = Next[x][j];
    }
    if(j == len[x])
        return i - len[x];
    else
        return -1;
}

void slove(){
    memset(vis,0,sizeof(vis));
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++)if(!vis[j]){
            if(hh(i,j)==-1) {
                vis[j]=1;ans=max(ans,j);
            }
            else break;
        }
    }
}
int main(){
    int t;
    cin>>t;
    int k=1;
    while(t--){
        scanf("%d",&n);
        ans=-1;
        for(int i=1;i<=n;i++){
            scanf("%s",s[i]);
            len[i]=strlen(s[i]);
            getNext(i);
        }
        slove();
        printf("Case #%d: %d\n",k++,ans);

    }
}