OJ-Problems-Source/HDOJ/2328_autoAC.cpp

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#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
#define MAXN 4010
#define N 210
int n;
int nex[MAXN];
char words[MAXN][N];
/*qsort*/
int cmp(const void *str1 , const void *str2){
return strlen((char *)str1)-strlen((char *)str2);
}
/*姹next*/
void getNext(char *str){
int len = strlen(str);
nex[0] = nex[1] = 0;
for(int i = 1 ; i < len ; i++){
int j = nex[i];
while(j && str[i] != str[j])
j = nex[j];
nex[i+1] = str[i] == str[j] ? j+1 : 0;
}
}
/*归芥*/
bool find(char *text , char *str){
int n = strlen(text);
int m = strlen(str);
int j = 0;
for(int i = 0 ; i < n ; i++){
while(j && text[i] != str[j])
j = nex[j];
if(str[j] == text[i])
j++;
if(j == m)
return true;
}
return false;
}
int main(){
int max;
char ans[MAXN];
while(scanf("%d%*c" , &n) && n){
for(int i = 0 ; i < n ; i++)
scanf("%s" , words[i]);
qsort(words , n , sizeof(words[0]) , cmp);
int pos;
char tmp[N];
int len = strlen(words[0]);
max = 0;
for(int i = 0 ; i < len ; i++){
memset(tmp , '\0' , sizeof(tmp));
pos = 0;
for(int j = i ; j < len ; j++){
tmp[pos++] = words[0][j];
getNext(tmp);
int vis = 1;
for(int k = 1 ; k < n ; k++){
if(!find(words[k] , tmp)){
vis = 0;
break;
}
}
if(vis && max < pos){
max = pos;
memcpy(ans , tmp , sizeof(tmp));
}
else if(vis && max == pos && strcmp(ans , tmp) > 0)
memcpy(ans , tmp , sizeof(tmp));
}
}
if(max)
printf("%s\n" , ans);
else
printf("IDENTITY LOST\n");
}
return 0;
}