KMP.
暴力strstr也轻松过.
//#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cstdlib> #include<algorithm> #include<iostream> #include<sstream> #include<cmath> #include<climits> #include<string> #include<map> #include<queue> #include<vector> #include<stack> #include<set> using namespace std; typedef long long ll; typedef pair<int,int> pii; #define pb(a) push_back(a) #define INF 0x1f1f1f1f #define lson idx<<1,l,mid #define rson idx<<1|1,mid+1,r #define PI 3.1415926535898 template<class T> T min(const T& a,const T& b,const T& c) { return min(min(a,b),min(a,c)); } template<class T> T max(const T& a,const T& b,const T& c) { return max(max(a,b),max(a,c)); } void debug() { #ifdef ONLINE_JUDGE #else freopen("d:\in.txt","r",stdin); // freopen("d:\out1.txt","w",stdout); #endif } int getch() { int ch; while((ch=getchar())!=EOF) { if(ch!=' '&&ch!=' ')return ch; } return EOF; } void GetNext(const char *s ,int *next) { int len=strlen(s); next[0]=next[1]=0; for(int i=2;i<=len;i++) { int j=next[i-1]; if(j&&s[j]!=s[i-1])j=next[j]; if(s[j]==s[i-1])next[i]=j+1; else next[i]=0; } } void reversal( char *s) { int len=strlen(s); for(int i=0,j=len-1;i<j;i++,j--) swap(s[i],s[j]); } void strcut(char *sub,char *p,char *ed) { int k=0; for(;p!=ed;p++,k++) { sub[k]=*p; } sub[k]=' '; } char dic[110][110]; int n; int judge(char *sub1) { int next1[110],next2[110]; char sub2[110]; int len=strlen(sub1); for(int i=0;i<len;i++) sub2[i]=sub1[len-i-1]; GetNext(sub1,next1); GetNext(sub2,next2); for(int k=1;k<n;k++) { int f1=0,f2=0; int j; j=0; for(int i=0;dic[k][i]!=' ';) { if(sub1[j]==dic[k][i]) { j++;i++; if(j==len) { f1=1;break; } }else { if(j==0)i++; else j=next1[j]; } } j=0; for(int i=0;dic[k][i]!=' ';) { if(sub2[j]==dic[k][i]) { j++;i++; if(j==len) { f2=1;break; } }else { if(j==0)i++; else j=next2[j]; } } if((!f1)&&(!f2))return 0; } return 1; } int main() { int t; scanf("%d",&t); for(int ca=1;ca<=t;ca++) { scanf("%d",&n); for(int i=0;i<n;i++) scanf("%s",dic[i]); int maxx=0; char sub[110]; int len=strlen(dic[0]); for(int i=0;i<len;i++) { for(int j=i+maxx+1;j<=len;j++) { strcut(sub,dic[0]+i,dic[0]+j); if(judge(sub)) { maxx=j-i; } } } printf("%d ",maxx); } return 0; }