【HDOJ】5046 Airport

DLX简单题目。

 /* 5046 */
 #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

 const int maxn = ;
 int N, K;
 __int64 X[maxn], Y[maxn];
 __int64 M[maxn][maxn];

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

     int n, sz;
     int S[maxc];

     int col[maxn];
     int L[maxn], R[maxn], U[maxn], D[maxn];

     int ansd;
     bool visit[maxc];

     void init(int n_) {
         n = n_;

         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) {
         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;
         }
     }

     int H() {
         int ret = ;

         memset(visit, false, sizeof(visit));

         for (int c=R[]; c!=; 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;
     }

     bool dfs(int d) {
         if (R[] == ) {
             return d<=K;
         }

         int delta = H();
         if (d+delta > K)
             return false;

         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]) {
             remove(i);
             for (int j=R[i]; j!=i; j=R[j]) {
                 remove(j);
             }
             if( dfs(d + ) )    return true;
             for (int j=L[i]; j!=i; j=L[j]) {
                 restore(j);
             }
             restore(i);
         }

         return false;
     }

 } DLX;

 DLX solver;

 __int64 Length(int i, int j) {
     return abs(X[i]-X[j]) + abs(Y[i]-Y[j]);
 }

 bool judge(__int64 d) {
     solver.init(N);

     rep(i, , N+) {
         vi columns;
         rep(j, , N+) {
             if (M[i][j] <= d) {
                 columns.pb(j);
             }
         }
         if (SZ(columns) > ) {
             solver.addRow(columns);
         }
     }

     return solver.dfs();
 }

 void solve() {
     rep(i, , N+) {
         M[i][i] = ;
         rep(j, , i)
             M[i][j] = M[j][i] = Length(i, j);
     }

     __int64 l, r, mid;
     __int64 ans;

     l = ;
     r = ans = 5e9;
     while (r >= l) {
         mid = (r + l)>>;
         if (judge(mid)) {
             ans = mid;
             r = mid - ;
         } else {
             l = mid + ;
         }
     }

     printf("%I64d\n", ans);
 }

 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 %d", &N, &K);
         rep(i, , N+)
             scanf("%I64d %I64d", &X[i], &Y[i]);
         printf("Case #%d: ", tt);
         solve();
     }

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

     return ;
 }