【HDOJ】3828 A + B problem

显然需要贪心，重叠越长越好，这样最终的串长尽可能短。
需要注意的是，不要考虑中间结果，显然是个状态dp。
先做预处理去重，然后求任意一对串的公共长度。

/* 3828 */
#include <iostream>
#include <sstream>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <deque>
#include <bitset>
#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 INF = 0x3f3f3f3f;
const int maxl = 70;
const int maxn = 16;
const int mod = 1000000009;
__int64 a[maxn];
char word[maxn][maxl];
string sw[maxn];
int nxt[maxl];
int Len[maxn];
bool visit[maxn];
int dp[1<<16][16];
int M[16][16];
int n;

void f(char *s, __int64 x) {
    int l = 0;
    while (x) {
        s[l] = (x & 1) + '0';
        ++l;
        x >>= 1;
    }
    s[l] = '';
    reverse(s, s+l);
}

void getnext(char *s) {
    int i = 0, j = -1;
    int l = strlen(s);
    
    nxt[0] = -1;
    while (i < l) {
        if (j==-1 || s[i]==s[j]) {
            ++i;
            ++j;
            nxt[i] = j;
        } else {
            j = nxt[j];
        }
    }
}

bool match(char *d, char *s, int ld, int ls) {
    int i = 0, j = 0;
    
    while (i < ld) {
        if (d[i] == s[j]) {
            ++i;
            ++j;
        } else {
            j = nxt[j];
            if (j == -1) {
                j = 0;
                ++i;
            }
        }
        if (j == ls)
            return true;
    }
    
    return false;
}

void cover() {
    memset(visit, false, sizeof(visit));
    rep(i, 0, n) {
        getnext(word[i]);
        rep(j, 0, n) {
            if (i == j)
                continue;
            if (match(word[j], word[i], Len[j], Len[i])) {
                visit[i] = true;
                break;
            }
        }
    }
    
    int nn = 0;
    rep(i, 0, n) {
        if (!visit[i]) {
            strcpy(word[nn], word[i]);
            Len[nn] = strlen(word[nn]);
            ++nn;
        }
    }
    n = nn;
}

bool judge(int l, char *sa, char *sb) {
    rep(i, 0, l) {
        if (sa[i] != sb[i])
            return false;
    }
    return true;
}

int LongFix(int a, int b) {
    per(l, 1, Len[a]) {
        if (Len[b]>=l && judge(l, word[a]+Len[a]-l, word[b]))
            return l;
    }

    return 0;
}

void calc() {
    rep(i, 0, n) {
        rep(j, 0, n) {
            if (i == j) {
                M[i][j] = Len[i];
                continue;
            }
            M[i][j] = LongFix(i, j);
        }
    }
}

void solve() {
    sort(a, a+n);
    n = unique(a, a+n) - a;
    rep(i, 0, n) {
        f(word[i], a[i]);
        Len[i] = strlen(word[i]);
    }
    cover();
    calc();
    
    int mst = 1 << n;
    
    memset(dp, INF, sizeof(dp));
    rep(i, 0, n)
        dp[1<<i][i] = Len[i];
        
    rep(i, 0, mst) {
        rep(j, 0, n) {
            if (dp[i][j]==INF || (i&(1<<j))==0)
                continue;
            
            rep(k, 0, n) {
                if (i & (1<<k))
                    continue;
                
                int nst = i | (1<<k);
                dp[nst][k] = min(dp[nst][k], dp[i][j]+Len[k]-M[k][j]);
            }
        }
    }
    
    rep(i, 0, n)
        sw[i] = string(word[i]);
        
    int st = mst - 1;
    int p = -1;
    
    string str = "";
    while (1) {
        int mn = INF, v;
        string tstr, mnstr;
        
        rep(i, 0, n) {
            if ((st & (1<<i)) == 0)
                continue;
            
            int tmp = dp[st][i];
            if (p >= 0) {
                tmp -= M[p][i];
                tstr = sw[i].substr(M[p][i]);
            } else {
                tstr = sw[i];
            }
            
            if (tmp<mn || (tmp==mn && tstr<mnstr)) {
                mn = tmp;
                mnstr = tstr;
                v = i;
            }
        }
        
        str += mnstr;
        p = v;
        st ^= (1 << v);
        if (st == 0)
            break;
    }
    
    int length = str.length(), base = 1;
    __int64 ans = 0;
    
    per(i, 0, length) {
        if (str[i] == '1')
            ans = (ans + base) % mod;
        base = (base + base) % mod;
    }
    
    printf("%I64d
", ans);
}

int main() {
    ios::sync_with_stdio(false);
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif
    
    while (cin >> n) {
        rep(i, 0, n)
            cin >> a[i];
        solve();
    }
    
    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif
    
    return 0;
}