【POJ】3294 Life Forms

后缀数组。

 /* 3294 */
 #include <iostream>
 #include <sstream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1

 const int maxl = ;
 const int maxs = ;
 const int maxn = maxl * maxs;
 char s[maxs][maxl];
 int id[maxn], pos[maxn], pn;
 bool visit[maxs];
 int a[maxn];
 int rank[maxn], height[maxn], sa[maxn];
 int wa[maxn], wb[maxn], wc[maxn], wv[maxn];
 int ns, ns_;

 bool cmp(int *r, int a, int b, int l) {
     return r[a]==r[b] && r[a+l]==r[b+l];
 }

 void da(int *r, int *sa, int n, int m) {
     int i, j, *x=wa, *y=wb, *t, p;

     for (i=; i<m; ++i) wc[i] = ;
     for (i=; i<n; ++i) wc[x[i]=r[i]]++;
     for (i=; i<m; ++i) wc[i] += wc[i-];
     for (i=n-; i>=; --i) sa[--wc[x[i]]] = i;
     for (j=,p=; p<n; j*=,m=p) {
         for (p=,i=n-j; i<n; ++i) y[p++] = i;
         for (i=; i<n; ++i) if (sa[i] >= j) y[p++] = sa[i]-j;
         for (i=; i<n; ++i) wv[i] = x[y[i]];
         for (i=; i<m; ++i) wc[i] = ;
         for (i=; i<n; ++i) wc[wv[i]]++;
         for (i=; i<m; ++i) wc[i] += wc[i-];
         for (i=n-; i>=; --i) sa[--wc[wv[i]]] = y[i];
         for (t=x,x=y,y=t, x[sa[]]=, p=, i=; i<n; ++i)
             x[sa[i]] = cmp(y, sa[i-], sa[i], j) ? p-:p++;
     }
 }

 void calheight(int *r, int *sa, int n) {
     int i, j, k = ;

     for (i=; i<=n; ++i) rank[sa[i]] = i;
     for (i=; i<n; height[rank[i++]]=k)
     for (k?k--:, j=sa[rank[i]-]; r[j+k]==r[i+k]; ++k) ;
 }

 bool check(int b, int e) {
     int cnt = ;

     memset(visit, false, sizeof(visit));
     rep(i, b, e+) {
         if (!visit[id[sa[i]]]) {
             visit[id[sa[i]]] = true;
             ++cnt;
         }
     }

     return cnt > ns_;
 }

 bool judge(int bound, int n) {
     bool ret = false;
     int b, e;

     b = e = ;
     rep(i, , n+) {
         if (height[i] >= bound) {
             e = i;
         } else {
             if (check(b, e)) {
                 if (!ret)
                     pn = ;
                 ret = true;
                 pos[pn++] = sa[b];
             }
             b = e = i;
         }
     }
     if (check(b, e)) {
         if (!ret)
             pn = ;
         ret = true;
         pos[pn++] = sa[b];
     }

     return ret;
 }

 void printSa(int n) {
     for (int i=; i<=n; ++i)
         printf("%d ", sa[i]);
     putchar('\n');
 }

 void printHeight(int n) {
     for (int i=; i<=n; ++i)
         printf("%d ", height[i]);
     putchar('\n');
 }

 void solve() {
     int n = , ml = ;

     if (ns == ) {
         puts(s[]);
         return ;
     }

     rep(i, , ns) {
         for (int j=; ; ++j) {
             if (s[i][j] == '\0') {
                 ml = max(ml, j);
                 break;
             }
             id[n] = i;
             a[n] = s[i][j] - 'a' + ;
             ++n;
         }
         id[n] = a[n] = i;
         ++n;
     }

     --n;
     da(a, sa, n+, );
     calheight(a, sa, n);

     #ifndef ONLINE_JUDGE
         // printSa(n);
         // printHeight(n);
         // printf("ml = %d\n", ml);
     #endif

     int l = , r = ml, mid;
     int ans = ;
     ns_ = ns >> ;

     while (l <= r) {
         mid = (l + r) >> ;
         if (judge(mid, n)) {
             ans = mid;
             l = mid + ;
         } else {
             r = mid - ;
         }
     }

     if (ans == ) {
         puts("?");
         return ;
     }

     char ch;

     rep(i, , pn) {
         rep(j, , ans) {
             ch = a[pos[i]+j] -  + 'a';
             putchar(ch);
         }
         putchar('\n');
     }
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     int t = ;

     while (scanf("%d", &ns)!=EOF && ns) {
         rep(i, , ns)
             scanf("%s", s[i]);
         if (t++)
             putchar('\n');
         solve();
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }

数据生成器。

 from random import randint, shuffle
 import shutil
 import string

 def GenDataIn():
     with open("data.in", "w") as fout:
         t = 20
         bound = 10**3
         lc = list(string.lowercase)
         for tt in xrange(t):
             n = randint(1, 10)
             fout.write("%d\n" % (n))
             for i in xrange(n):
                 length = randint(20, 50)
                 line = ""
                 for j in xrange(length):
                     idx = randint(0, 25)
                     line += lc[idx]
                 fout.write("%s\n" % (line))
         fout.write("0\n")

 def MovDataIn():
     desFileName = "F:\eclipse_prj\workspace\hdoj\data.in"
     shutil.copyfile("data.in", desFileName)

 if __name__ == "__main__":
     GenDataIn()
     MovDataIn()