我的：

int tail[kMaxN * 20], pre[kMaxM], to[kMaxM], val[kMaxM], dep[kMaxN * 20], cur[kMaxN * 20];
bool vis[kMaxN * 20];

void add(int u, int v, int w) {
  to[++tot] = v, pre[tot] = tail[u], val[tot] = w, tail[u] = tot;
}

void adde(int u, int v, int w) {
  add(u, v, w), add(v, u, 0);
}

bool bfs() {
  std::queue<int> q;
  for (int i = 1; i <= cnt; ++i) {
    dep[i] = kInf, cur[i] = tail[i], vis[i] = 0;
  }
  q.emplace(s), dep[s] = 0, vis[s] = 1;
  while (!q.empty()) {
    int u = q.front();
    q.pop();
    for (int i = tail[u]; i; i = pre[i]) {
      int v = to[i], w = val[i];
      if (!w || vis[v]) continue;
      vis[v] = 1, dep[v] = dep[u] + 1, q.emplace(v);
    }
  }
  return vis[t];
}

int dfs(int u, int flow) {
  if (u == t || !flow) return flow;
  int ret = 0;
  for (int &i = cur[u]; i && flow; i = pre[i]) {
    int v = to[i], w = val[i];
    if (dep[v] == dep[u] + 1 && w) {
      int tmp = dfs(v, std::min(w, flow));
      if (!tmp) dep[v] = 0;
      flow -= tmp, ret += tmp;
      val[i] -= tmp, val[i ^ 1] += tmp;
    }
  }
  return ret;
}

那个人的：

struct Graph {
    struct Node {
        int v, w, nxt;
    };
    std::vector<int> head;
    std::vector<Node> edge;
    Graph() {
    }
    Graph(int n) : head(n + 1, -1){};
    void resize(int n) {
        head.assign(n + 1, -1);
    }
    void add(int u, int v, int w) {
        if (head.size() < u) {
            head.reserve(u * 2);
        }
        edge.emplace_back(Node{v, w, head[u]});
        head[u] = edge.size() - 1;
    }

    void add_flow(int u, int v, int w) {
        add(u, v, w);
        add(v, u, 0);
    }
};
namespace NetworkFlow {
std::vector<int> level;
bool bfs(int S, int T, const Graph &G) {
    level.assign(G.head.size(), 0);
    level[S] = 1;
    std::queue<int> q;
    q.push(S);
    while (!q.empty()) {
        int now = q.front();
        q.pop();
        for (int i = G.head[now]; ~i; i = G.edge[i].nxt) {
            int v = G.edge[i].v;
            if (!level[v] && G.edge[i].w) {
                level[v] = level[now] + 1;
                q.push(v);
            }
        }
    }
    return level[T];
}
std::vector<int> cur;
int dfs(int x, int T, int maxflow, Graph &G) {
    if (x == T) {
        return maxflow;
    }
    int res = 0;
    for (int i = cur[x]; ~i && res < maxflow; i = G.edge[i].nxt) {
        cur[x] = i;
        int v  = G.edge[i].v;
        if (G.edge[i].w && level[v] == level[x] + 1) {
            int x = dfs(v, T, std::min(G.edge[i].w, maxflow - res), G);
            if (x) {
                G.edge[i].w -= x;
                G.edge[i ^ 1].w += x;
                res += x;
            }
        }
    }
    if (res < maxflow) {
        level[x] = -1;
    }
    return res;
}
int MaxFlow(const int S, const int T, const Graph &G) {
    cur.resize(G.head.size());
    level.resize(G.head.size());
    Graph tmpG = G;
    int res    = 0;
    while (bfs(S, T, tmpG)) {
        cur.assign(tmpG.head.begin(), tmpG.head.end());
        int x;
        while (x = dfs(S, T, INF, tmpG)) {
            res += x;
        }
    }
    return res;
}
} // namespace NetworkFlow

都是在 CF793G 里面的一个点数为 311661 边数为 1199499 的图里面跑，他的只要150ms，我的到了6500ms的时限了还没跑完！

这是为什么啊啊啊