POJ3080 Blue Jeans

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <list>
#include <deque>
#include <queue>
#include <cctype>
#include <map>
#include <set>
#include <bitset>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iomanip>
#include <cstdlib>
#include <ctime>
#include <cassert>
#include <limits>
#include <fstream>

using namespace std;

#define mem(A, X) memset(A, X, sizeof A)
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define foreach(e,x) for(__typeof(x.begin()) e=x.begin();e!=x.end();++e)
#define sz(x) (int)((x).size())
#define sl(a) strlen(a)
#define rep(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#define Rep(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define min3(a,b,c) min(a,min(b,c))
#define max3(a,b,c) max(a,max(b,c))
#define dbg(a) cout << a << endl;
#define fi first
#define se second
typedef long long int64;
int gcd(const int64 &a, const int64 &b) {return b == 0 ? a : gcd(b, a % b);}
int64 int64pow(int64 a, int64 b){if(b == 0) return 1;int64 t = int64pow(a, b / 2);if(b % 2) return t * t * a;return t * t;}
const int inf = 1 << 30;
const double eps = 1e-8;
const double pi = acos(-1.0);
const int MAX_N = 65;

char text[15][MAX_N], pattern[MAX_N];
int m, T, next[MAX_N], ans, tmpans;
char result[MAX_N];

void GetNext(char *pattern)
{
int i = 0, j = -1;
next[0] = -1;
int LenP = strlen(pattern);

while (i < LenP) {
if (j == -1 || pattern[i] == pattern[j]) {
++i;
++j;
next[i] = j;
}
else {
j = next[j];
}
}
}

void KMP(char *pattern, char *text)
{
int LenP = strlen(pattern), LenT = strlen(text);
int i = 0, j = 0, n = 0;
while (i < LenT && j < LenP) {
if (j == -1 || text[i] == pattern[j]) {
++i;
++j;
}
else {
j = next[j];
}
if(j > n) n = j;
}
if(n < tmpans) tmpans = n;
}

void solve()
{
rep(i, 0, m) {
scanf("%s", text[i]);
}
ans = 0;
Rep(i, 0, 57) {
strcpy(pattern, text[0] + i);
GetNext(pattern);
tmpans = 100;
rep(k, 1, m) {
KMP(pattern, text[k]);
}
if(ans < tmpans)  {
ans = tmpans;
strncpy(result, text[0] + i, ans);
result[ans] = '\0';
}
else if(ans == tmpans)  { //  存在多个最长公共子串，输出字典序最小的
char tmp[MAX_N];
strncpy(tmp, text[0] + i, ans);
tmp[ans] = '\0';
if(strcmp(tmp, result) < 0)
strcpy(result, tmp);
}
}
if(ans >= 3)
printf("%s\n", result);
else
printf("no significant commonalities\n");
}

int main()
{
cin >> T;
while (cin >> m) {
solve();
}
return 0;
}