poj 2185 Milking Grid (最小覆盖子矩形，kmp)

 1/* ***********************************************
 2Author :111qqz
 3Created Time :2016年08月10日 星期三 23时46分47秒
 4File Name :code/poj/2185.cpp
 5************************************************ */
 6
 7#include <cstdio>
 8#include <cstring>
 9#include <iostream>
10#include <algorithm>
11#include <vector>
12#include <queue>
13#include <stack>
14#include <set>
15#include <map>
16#include <string>
17#include <cmath>
18#include <cstdlib>
19#include <deque>
20#include <ctime>
21#define fst first
22#define sec second
23#define lson l,m,rt<<1
24#define rson m+1,r,rt<<1|1
25#define ms(a,x) memset(a,x,sizeof(a))
26typedef long long LL;
27#define pi pair < int ,int >
28#define MP make_pair
29
30using namespace std;
31const double eps = 1E-8;
32const int dx4[4]={1,0,0,-1};
33const int dy4[4]={0,-1,1,0};
34const int inf = 0x3f3f3f3f;
35const int N=1E4+7;
36char s[N][80];
37int n,m;
38int nxt[N];
39void getrownxt(int row,int n)
40{
41    int i = 0 ;
42    int j = -1;
43    nxt[0] = -1;
44    while (i<n)
45	if (j==-1||s[row][i]==s[row][j]) nxt[++i]=++j;
46	else j = nxt[j];
47}
48void getcolnxt(int col,int n)
49{
50    int i = 0 ;
51    int j = -1;
52    nxt[0] = -1;
53    while (i<n)
54	if (j==-1||s[i][col]==s[j][col]) nxt[++i]=++j;
55	else j = nxt[j];
56}
57int gcd( int a,int b)
58{
59    if (a%b==0) return b;
60    return gcd(b,a%b);
61}
62int lcm(int a,int b)
63{
64    return a/gcd(a,b)*b;  //蒟蒻的自我修养
65}
66int main()
67{
68	#ifndef  ONLINE_JUDGE 
69	freopen("code/in.txt","r",stdin);
70  #endif
71
72	cin>>n>>m;
73	for ( int i = 0 ; i < n ; i++) scanf("%s",s[i]);
74
75	int L = 1;
76	for ( int i =  0 ; i < n ; i++)
77	{
78	    getrownxt(i,m);
79	    L = lcm(L,m-nxt[m]);
80	}
81	int R = 1;
82	for ( int i = 0 ; i < m ; i++)
83	{
84	    getcolnxt(i,n);
85	    R = lcm(R,n-nxt[n]);
86	}
87
88//	cout<<"L:"<<L<<" R:"<<R<<endl;
89	L = min(L,m);
90	R = min(R,n);
91	printf("%d\n",L*R);
92
93
94
95  #ifndef ONLINE_JUDGE  
96  fclose(stdin);
97  #endif
98    return 0;
99}