牛客-德育分博弈政治课

题目传送门

sol:根据题意建立流量网络然后跑网络流，这两天刚学的网络流，练练手。

• 网络最大流

  #include <bits/stdc++.h>
  using namespace std;
  typedef long long LL;
  typedef pair<int, int> PII;
  const int INF = 0x3f3f3f3f;
  map<int, int> mp;
  char ss[2000010];
  struct {
      int v, w, n;
  } edge[2010];
  int head[2010], tot;
  int dis[2010];
  int s, t;
  void add_edge(int u, int v, int w) {
      int i = tot ++;
      edge[i].v = v;
      edge[i].w = w;
      edge[i].n = head[u];
      head[u] = i;
  }
  bool bfs() {
      queue<int> que;
      memset(dis, -1, sizeof(dis));
      dis[t] = 0; que.push(t);
      while (!que.empty()) {
          int u = que.front();
          que.pop();
          for (int i = head[u]; i != -1; i = edge[i].n) {
              int v = edge[i].v, w = edge[i ^ 1].w;
              if (dis[v] != -1 || w == 0) continue;
              dis[v] = dis[u] + 1;
              que.push(v);
          }
      }
      return dis[s] != -1;
  }
  int dfs(int u, int k) {
      if (u == t) return k;
      for (int i = head[u]; i != -1; i = edge[i].n) {
          int v = edge[i].v, w = edge[i].w;
          if (dis[v] + 1 == dis[u] && w) {
              int k = dfs(v, min(k, w));
              if (k > 0) {
                  edge[i].w -= k;
                  edge[i ^ 1].w += k;
                  return k;
              }
          }
      }
      return 0;
  }
  bool slove() {
      int c[10]; memset(c, 0, sizeof(c));
      memset(head, -1, sizeof(head)); tot = 0;
      scanf("%s", ss);
      for (int i = 0; ss[i]; i++) c[ss[i] ^ '0'] ++;
      s = 0, t = mp.size() + 10;
      for (int i = 1; i < 10; i++) {
          if (c[i]) {
              add_edge(s, i, c[i]);
              add_edge(i, s, 0);
          }
      }
      int index = 10;
      for (auto p : mp) {
          for (int i = 1; i < 10; i++) {
              if (p.first & (1 << i)) {
                  add_edge(i, index, p.second);
                  add_edge(index, i, 0);
              }
          }
          add_edge(index, t, p.second);
          add_edge(t, index, 0);
          index ++;
      }
      int res = 0;
      while (bfs()) res += dfs(s, INF);
      return res == strlen(ss);
  }
  int main() {
      int n, m; scanf("%d%d%*c", &n, &m);
      for (int i = 1; i <= n; i++) {
          int k = 0;
          for (int j = 1; j <= 6; j++)
              k |= 1 << (getchar() ^ '0');
          mp[k] ++; getchar();
      }
      for (int i = 1; i <= m; i++)
          puts(slove() ? "dyf" : "zzk");
      return 0;
  }