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

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int N=503;
 4 const int M=2003;
 5
 6 char s[N][M];
 7 bool vis[N];
 8 int Next[N][M];
 9 int len[N];
10 int n;
11 int ans;
12
13 void getNext(int x){
14     int j, k;
15     j = 0; k = -1; Next[x][0] = -1;
16     while(j < len[x])
17         if(k == -1 || s[x][j] == s[x][k])
18             Next[x][++j] = ++k;
19         else
20             k = Next[x][k];
21 }
22
23 int hh(int x,int y)//x是子串,y是母串
24 {
25     int i = 0, j = 0;
26     while(i < len[y] && j < len[x])
27     {
28         if(j == -1 || s[y][i] == s[x][j])
29         {
30             i++; j++;
31         }
32         else
33             j = Next[x][j];
34     }
35     if(j == len[x])
36         return i - len[x];
37     else
38         return -1;
39 }
40
41 void slove(){
42     memset(vis,0,sizeof(vis));
43     for(int i=1;i<=n;i++){
44         for(int j=i+1;j<=n;j++)if(!vis[j]){
45             if(hh(i,j)==-1) {
46                 vis[j]=1;ans=max(ans,j);
47             }
48             else break;
49         }
50     }
51 }
52 int main(){
53     int t;
54     cin>>t;
55     int k=1;
56     while(t--){
57         scanf("%d",&n);
58         ans=-1;
59         for(int i=1;i<=n;i++){
60             scanf("%s",s[i]);
61             len[i]=strlen(s[i]);
62             getNext(i);
63         }
64         slove();
65         printf("Case #%d: %d\n",k++,ans);
66
67     }
68 }