牛客&科大讯飞杯&SHU、L动物森友会【二分】【网络流】

  1 #include <bits/stdc++.h>
  2 #define dbg(x) cout << #x << "=" << x << endl
  3 #define eps 1e-8
  4 #define pi acos(-1.0)
  5  
  6 using namespace std;
  7 typedef long long LL;
  8  
  9 const LL inf = 1e14;
 10  
 11 template<class T>inline void read(T &res)
 12 {
 13     char c;T flag=1;
 14     while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0';
 15     while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag;
 16 }
 17  
 18 namespace _buff {
 19     const size_t BUFF = 1 << 19;
 20     char ibuf[BUFF], *ib = ibuf, *ie = ibuf;
 21     char getc() {
 22         if (ib == ie) {
 23             ib = ibuf;
 24             ie = ibuf + fread(ibuf, 1, BUFF, stdin);
 25         }
 26         return ib == ie ? -1 : *ib++;
 27     }
 28 }
 29  
 30 int qread() {
 31     using namespace _buff;
 32     int ret = 0;
 33     bool pos = true;
 34     char c = getc();
 35     for (; (c < '0' || c > '9') && c != '-'; c = getc()) {
 36         assert(~c);
 37     }
 38     if (c == '-') {
 39         pos = false;
 40         c = getc();
 41     }
 42     for (; c >= '0' && c <= '9'; c = getc()) {
 43         ret = (ret << 3) + (ret << 1) + (c ^ 48);
 44     }
 45     return pos ? ret : -ret;
 46 }
 47  
 48 const int maxn = 200007;
 49  
 50 int n, m;
 51 int s, t;
 52  
 53 struct edge{
 54     int from,to;
 55     LL cap,flow;
 56 };
 57  
 58 map<int, int> vis;
 59  
 60 struct DINIC {
 61     int head[maxn << 1], nxt[maxn << 1];
 62     int edge[maxn << 1], cnt;
 63     LL cap[maxn << 1], depth[maxn << 1];
 64  
 65     void init() {
 66         cnt = 1;
 67         memset(head, 0, sizeof(head));
 68         memset(depth, 0, sizeof(depth));
 69         memset(cap, 0, sizeof(cap));
 70     }
 71  
 72     void BuildGraph(int u, int v, LL w) {
 73         ++cnt;
 74         edge[cnt] = v;
 75         nxt[cnt] = head[u];
 76         cap[cnt] = w;
 77         head[u] = cnt;
 78  
 79         ++cnt;
 80         edge[cnt] = u;
 81         nxt[cnt] = head[v];
 82         cap[cnt] = 0;
 83         head[v] = cnt;
 84     }
 85  
 86     queue<int> q;
 87  
 88     bool bfs() {
 89         memset(depth, 0, sizeof(depth));
 90         depth[s] = 1;
 91         q.push(s);
 92         while(!q.empty()) {
 93             int u = q.front();
 94             q.pop();
 95             for ( int i = head[u]; i; i = nxt[i] ) {
 96                 int v = edge[i];
 97                 if(depth[v]) {
 98                     continue;
 99                 }
100                 if(cap[i]) {
101                     depth[v] = depth[u] + 1;
102                     q.push(v);
103                 }
104             }
105         }
106         return depth[t];
107     }
108  
109     LL dfs(int u, LL dist) {
110         if(u == t) {
111             return dist;
112         }
113         LL flow = 0;
114         for ( int i = head[u]; i && dist; i = nxt[i] ) {
115             if(cap[i] == 0)
116                 continue;
117             int v = edge[i];
118             if(depth[v] != depth[u] + 1) {
119                 continue;
120             }
121             LL res = dfs(v, min(cap[i], dist));
122             cap[i] -= res;
123             cap[i ^ 1] += res;
124             //printf("cap[%d]:%d\n",t, cap[t]);
125             dist -= res;
126             flow += res;
127         }
128         return flow;
129     }
130  
131     LL maxflow() {
132         LL ans = 0;
133         while(bfs()) {
134             ans += dfs(s, inf);
135         }
136         return ans;
137     }
138 } dinic;
139  
140 int e;
141 LL c[maxn], mi[maxn];
142 int a[maxn][10];
143 LL tot = 0;
144  
145 void BuildGraph(LL limit) {
146     dinic.init();
147     s = 0, t = n + 8;
148     for ( int i = 1; i <= 7; ++i ) {
149         LL day = limit / 7;
150         if(limit % 7 >= i) {
151             day++;
152         }
153         dinic.BuildGraph(s, i, day * e);
154     }
155     for ( int i = 1; i <= n; ++i ) {
156         for ( int j = 1; j <= mi[i]; ++j ) {
157             dinic.BuildGraph(a[i][j], i + 7, inf);
158         }
159         dinic.BuildGraph(i + 7, t, c[i]);
160     }
161 }
162  
163 bool check(LL mid) {
164     if(e * mid < tot) {
165         return false;
166     }
167     BuildGraph(mid);
168     LL temp = dinic.maxflow();
169     //if(temp < 100) dbg(temp);
170     return temp >= tot;
171 }
172  
173 int main()
174 {
175     //freopen("data.txt", "r", stdin);
176     dinic.init();
177     read(n); read(e);
178     s = 0, t = n + 8;
179     for ( int i = 1; i <= n; ++i ) {
180         read(c[i]); read(mi[i]);
181         tot += c[i];
182         for ( int j = 1; j <= mi[i]; ++j ) {
183             read(a[i][j]);
184         }
185     }
186     LL l = 1, r = tot / e, mid, ans = 0;
187     while(l <= r) {
188         mid = (l + r) >> 1;
189         if(check(mid)) {
190             r = mid - 1;
191             ans = mid;
192         }
193         else {
194             l = mid + 1;
195         }
196     }
197     cout << ans << endl;
198     return 0;
199 }