【HDOJ】2828 Lamp

DLX简单题目。

 /*  */
 #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 INF = 0x3f3f3f3f;

 typedef struct {
     static const int maxn = 1e6+;

     int L[maxn], R[maxn], U[maxn], D[maxn];
     int H[maxn];
     int row[maxn], col[maxn], S[maxn];

     bool visit[];
     int sz;
     int ans[maxn], ansd;

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

         memset(S, , sizeof(S));
         memset(visit, false, sizeof(visit));
         memset(H, -, sizeof(H));
         R[n] = ;
         L[] = n;
         sz = n + ;
     }

     void link(int r, int c) {
         U[sz] = c;
         D[sz] = D[c];
         U[D[c]] = sz;
         D[c] = sz;
         if (H[r] < ) {
             H[r] = L[sz] = R[sz] = sz;
         } else {
             L[sz] = H[r];
             R[sz] = R[H[r]];
             L[R[H[r]]] = sz;
             R[H[r]] = sz;
         }

         ++S[c];
         col[sz] = c;
         row[sz] = r;
         ++sz;
     }

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

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

     bool dfs(int cur) {
         if (!R[]) {
             return true;
         }

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

         for (int i=D[c]; i!=c; i=D[i]) {
             if (visit[row[i]^])
                 continue;
             visit[row[i]] = true;
             remove_(i);
             for (int j=R[i]; j!=i; j=R[j])
                 remove_(j);
             if (dfs(cur+))    return true;
             for (int j=L[i]; j!=i; j=L[j])
                 restore_(j);
             restore_(i);
             visit[row[i]] = false;
         }

         return false;
     }

 } DLX;

 DLX solver;

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

     int n, m;
     int ln, k;
     char op[];
     bool flag;

     while (scanf("%d %d", &n, &m)!=EOF) {
         solver.init(n);
         rep(i, , n+) {
             scanf("%d", &ln);
             while (ln--) {
                 scanf("%d %s", &k, op);
                 --k;
                 if (op[] == 'N') {
                     solver.link(k<<, i);
                 } else {
                     solver.link(k<<|, i);
                 }
             }
         }

         flag = solver.dfs();
         if (flag) {
             if (solver.visit[]) {
                 printf("OFF");
             } else {
                 printf("ON");
             }
             m <<= ;
             for (int i=; i<m; i+=) {
                 if (solver.visit[i]) {
                     printf(" ON");
                 } else {
                     printf(" OFF");
                 }
             }
             putchar('\n');
         } else {
             puts("-1");
         }
     }

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

     return ;
 }