【HDOJ】3957 Street Fighter

一定要注意审题啊，题目说的是选出做少的英雄打败其余处在任何模式下的英雄。
共有Sigma(num of model)个方案，每个方案有Sigma(num of model)+n个决策。
挺不错的一道精确覆盖的题目，最近发现精确覆盖很有意思。

 /* 3957 */
 #include <iostream>
 #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

 typedef struct {
     static const int maxc = *+;
     static const int maxr = ;
     static const int maxn = *+;

     int nmodel;
     int n, sz;
     int S[maxc];

     int col[maxn];
     int L[maxn], R[maxn], U[maxn], D[maxn];
     bool visit[maxc];

     int ansd;

     void init(int nmodel_, int n_) {
         ansd = INT_MAX;
         n = n_;
         nmodel = nmodel_;

         rep(i, , n+) {
             L[i] = i - ;
             R[i] = i + ;
             U[i] = i;
             D[i] = i;
             col[i] = i;
         }
         L[] = n;
         R[n] = ;

         sz = n + ;
         memset(S, , sizeof(S));
     }

     void addRow(vi columns) {
         int first = sz;
         int size = SZ(columns);

         rep(i, , size) {
             int c = columns[i];

             L[sz] = sz - ;
             R[sz] = sz + ;

             D[sz] = c;
             U[sz] = U[c];
             D[U[c]] = sz;
             U[c] = sz;

             col[sz] = c;

             ++S[c];
             ++sz;
         }

         L[first] = sz - ;
         R[sz - ] = first;
     }

     void remove(int c) {
         L[R[c]] = L[c];
         R[L[c]] = R[c];
         for (int i=D[c]; i!=c; i=D[i]) {
             for (int j=R[i]; j!=i; j=R[j]) {
                 U[D[j]] = U[j];
                 D[U[j]] = D[j];
                 --S[col[j]];
             }
         }
     }

     void restore(int c) {
         L[R[c]] = c;
         R[L[c]] = c;
         for (int i=D[c]; i!=c; i=D[i]) {
             for (int j=R[i]; j!=i; j=R[j]) {
                 U[D[j]] = j;
                 D[U[j]] = j;
                 ++S[col[j]];
             }
         }
     }

     void remove_col(int c) {
         for (int i=D[c]; i!=c; i=D[i]) {
             L[R[i]] = L[i];
             R[L[i]] = R[i];
         }
     }

     void restore_col(int c) {
         for (int i=D[c]; i!=c; i=D[i]) {
             L[R[i]] = i;
             R[L[i]] = i;
         }
     }

     int H() {
         // return 0;
         int ret = ;

         memset(visit, false, sizeof(visit));
         for (int c=R[]; c!=&&c<=nmodel; c=R[c]) {
             if (visit[c])
                 continue;
             ++ret;
             visit[c] = true;
             for (int i=D[c]; i!=c; i=D[i]) {
                 for (int j=R[i]; j!=i; j=R[j])
                     visit[col[j]] = true;
             }
         }

         return ret;
     }

     void dfs(int d) {
         if (R[]== || R[]>nmodel) {
             ansd = min(ansd, d);
             return ;
         }

         int delta = H();

         if (d+delta >= ansd)
             return ;

         int c = R[];
         for (int i=R[]; i!=&&i<=nmodel; i=R[i]) {
             if (S[i] < S[c])
                 c = i;
         }

         for (int i=D[c]; i!=c; i=D[i]) {
             remove_col(i);
             for (int j=R[i]; j!=i; j=R[j]) {
                 if (col[j] <= nmodel)
                     remove_col(j);
             }
             for (int j=R[i]; j!=i; j=R[j]) {
                 if (col[j] > nmodel)
                     remove(col[j]);
             }
             dfs(d + );
             for (int j=L[i]; j!=i; j=L[j]) {
                 if (col[j] > nmodel)
                     restore(col[j]);
             }
             for (int j=L[i]; j!=i; j=L[j]) {
                 if (col[j] <= nmodel)
                     restore_col(j);
             }
             restore_col(i);
         }
     }

     void solve() {
         ansd = INT_MAX;
         dfs();
     }

 } DLX;

 typedef struct {
     int m, k[];
     pii p[][];
 } hero_t;

 DLX solver;
 int ID[][];
 int nmodel, n;
 hero_t hero[];

 void solve() {
     solver.init(nmodel, n+nmodel);

     rep(i, , n) {
         rep(j, , hero[i].m) {
             // each model has a plan
             vi columns;
             // cover i-th hero
             columns.pb(nmodel+i+);
             // cover 0-th plan
             columns.pb(ID[i][]);
             // may cover 1-th plan
             if (hero[i].m == )
                 columns.pb(ID[i][]);
             rep(k, , hero[i].k[j]) {
                 int role_id = hero[i].p[j][k].fir;
                 int model_id = hero[i].p[j][k].sec;
                 columns.pb(ID[role_id][model_id]);
             }

             solver.addRow(columns);
         }
     }

     solver.solve();

     printf("%d\n", solver.ansd);
 }

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

     int t;

     scanf("%d", &t);
     rep(tt, , t+) {
         scanf("%d", &n);
         nmodel = ;
         rep(i, , n) {
             scanf("%d", &hero[i].m);
             rep(j, , hero[i].m) {
                 scanf("%d", &hero[i].k[j]);
                 rep(k, , hero[i].k[j])
                     scanf("%d %d", &hero[i].p[j][k].fir, &hero[i].p[j][k].sec);
                 ID[i][j] = ++nmodel;
             }
         }
         printf("Case %d: ", tt);
         solve();
     }

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

     return ;
 }