BZOJ 3218: a + b Problem

Posted 2020-08-27 You Siki

3218: a + b Problem

Time Limit: 20 Sec  Memory Limit: 40 MB
Submit: 1280  Solved: 481
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用可持久化线段树优化边的数量,跑最小割求答案.

 

  1 #include <cstdio>
  2 #include <cstring>
  3 
  4 namespace read
  5 {
  6     inline char Char(void)
  7     {
  8         static const int siz = 1 << 20;
  9         
 10         static char buf[siz];
 11         static char *hd = buf + siz;
 12         static char *tl = buf + siz;
 13         
 14         if (hd == tl)
 15             fread(hd = buf, 1, siz, stdin);
 16         
 17         return *hd++;
 18     }
 19     
 20     inline int Int(void)
 21     {
 22         register int ret = 0, neg = 0, c = Char();
 23         
 24         for (; c < 48; c = Char())
 25             if (c == ‘-‘)neg ^= true;
 26         
 27         for (; c > 47; c = Char())
 28             ret = ret * 10 + c - ‘0‘;
 29         
 30         return neg ? -ret : ret;
 31     }
 32 }
 33 
 34 const int inf = 1e9 + 7;
 35 
 36 namespace network 
 37 {
 38     int S, T;
 39     int hd[200005];
 40     int to[1000005];
 41     int nt[1000005];
 42     int fl[1000005];
 43     
 44     inline void add(int u, int v, int f)
 45     {
 46         static int edge = 0, init = 1;
 47         
 48         if (init)memset(hd, -1, sizeof(hd)), init = 0;
 49         
 50         nt[edge] = hd[u]; to[edge] = v; fl[edge] = f; hd[u] = edge++;
 51         nt[edge] = hd[v]; to[edge] = u; fl[edge] = 0; hd[v] = edge++;
 52     }
 53     
 54     int dep[200005];
 55     
 56     inline bool bfs(void)
 57     {
 58         static int que[200005], l, r;
 59         memset(dep, 0, sizeof(dep));
 60         dep[que[l = 0] = S] = r = 1;
 61         
 62         while (l != r)
 63         {
 64             int u = que[l++], v; 
 65             
 66             for (int i = hd[u]; ~i; i = nt[i])
 67                 if (fl[i] && !dep[v = to[i]])
 68                     dep[que[r++] = v] = dep[u] + 1;
 69         }
 70         
 71         return dep[T];
 72     }
 73     
 74     inline int min(const int &a, const int &b)
 75     {
 76         return a < b ? a : b;
 77     }
 78     
 79     int cur[200005];
 80     
 81     int dfs(int u, int f)
 82     {
 83         if (u == T || !f)
 84             return f;
 85         
 86         int used = 0, flow, v;
 87         
 88         for (int i = cur[u]; ~i; i = nt[i])
 89             if (fl[i] && dep[v = to[i]] == dep[u] + 1)
 90             {
 91                 flow = dfs(v, min(f - used, fl[i]));
 92                 
 93                 used += flow;
 94                 fl[i] -= flow;
 95                 fl[i^1] += flow;
 96                 
 97                 if (fl[i])
 98                     cur[u] = i;
 99                 
100                 if (f == used)
101                     return f;
102             }
103         
104         if (!used)
105             dep[u] = 0;
106         
107         return used;
108     }
109     
110     inline long long maxFlow(void)
111     {
112         long long maxFlow = 0, newFlow;
113         
114         while (bfs())
115         {
116             memcpy(cur, hd, sizeof(cur));
117             
118             while (newFlow = dfs(S, inf))
119                 maxFlow += newFlow;
120         }
121         
122         return maxFlow;
123     }
124     
125     inline long long minCut(void)
126     {
127         return maxFlow();
128     }
129 }
130 
131 int pos[5005][2], ID;
132 
133 namespace segtree
134 {
135     struct node
136     {
137         int id;
138         int cnt;
139         node *ls;
140         node *rs;
141     };
142     
143     node *root[5005];
144     
145     inline node *newnode(int _cnt, node *_ls, node *_rs)
146     {
147         static node buf[200005], *hd = buf;
148         
149         hd->ls = _ls;
150         hd->rs = _rs;
151         hd->id = ++ID;
152         hd->cnt = _cnt;
153         
154         return hd++;
155     }
156     
157     node *insert(node *f, int l, int r, int pos, int fr)
158     {
159         node *ret;
160         
161         if (l == r)
162             ret = newnode(f->cnt + 1, 0, 0);
163         else
164         {
165             int mid = (l + r) >> 1;
166             
167             if (pos <= mid)
168                 ret = newnode(f->cnt + 1, insert(f->ls, l, mid, pos, fr), f->rs);
169             else
170                 ret = newnode(f->cnt + 1, f->ls, insert(f->rs, mid + 1, r, pos, fr));
171         }
172         
173         network::add(fr, ret->id, inf);
174         network::add(f->id, ret->id, inf);
175         
176         return ret;
177     }
178     
179     void travel(node *t, int l, int r, int x, int y, int to)
180     {
181         if (t->cnt == 0)return;
182         
183         if (l == x && r == y)
184             network::add(t->id, to, inf);
185         else
186         {
187             int mid = (l + r) >> 1;
188             
189             if (y <= mid)
190                 travel(t->ls, l, mid, x, y, to);
191             else if (x > mid)
192                 travel(t->rs, mid + 1, r, x, y, to);
193             else
194             {
195                 travel(t->ls, l, mid, x, mid, to);
196                 travel(t->rs, mid + 1, r, mid + 1, y, to);
197             }
198         }
199     }
200     
201     inline void init(void)
202     {
203         memset(root, 0, sizeof(root));
204         root[0] = newnode(0, 0, 0);
205         root[0]->ls = root[0];
206         root[0]->rs = root[0];
207     }
208 }
209 
210 signed main(void) 
211 {
212     int n = read::Int();
213     
214     long long answer = 0;
215     
216     for (int i = 1; i <= n; ++i)
217         pos[i][0] = ++ID,
218         pos[i][1] = ++ID;
219     
220     segtree::init();
221     
222     using network::S;
223     using network::T;
224     
225     S = 0, T = ++ID;
226     
227     for (int i = 1; i <= n; ++i)
228     {
229         using read::Int;
230         using network::add;
231         using segtree::root;
232         using segtree::insert;
233         using segtree::travel;
234         
235         int a = Int();
236         int b = Int();
237         int w = Int();
238         int l = Int();
239         int r = Int();
240         int p = Int();
241         
242         answer += w;
243         answer += b;
244         
245         add(S, pos[i][0], w);
246         add(pos[i][0], T, b);
247         add(pos[i][1], pos[i][0], p);
248         
249         static const int mx = 1000000000;
250         
251         root[i] = insert(root[i - 1], 0, mx, a, pos[i][0]);
252         travel(root[i - 1], 0, mx, l, r, pos[i][1]);
253     }
254     
255     printf("%lld\n", answer - network::minCut());
256 }
257 /* 
258 Sample Input
259 10
260 0 1 7 3 9 2
261 7 4 0 9 10 5
262 1 0 4 2 10 2
263 7 9 1 5 7 2
264 6 3 5 3 6 2
265 6 6 4 1 8 1
266 6 1 6 0 6 5
267 2 2 5 0 9 3
268 5 1 3 0 2 5
269 5 6 7 1 1 2
270 
271 Sample Output
272 55
273 */

 

@Author: YouSiki