#include <bits/stdc++.h>

using namespace std;

#define orz puts("---------------------")

template <typename Ty, int Siz>
struct Graph {
	struct Edge {
		int to, nxt;
		Ty w, cost;
	} e[Siz << 1];
	
	int head[Siz], now[Siz], cnt;
	int S, T;
	Ty inf;
	Ty dis[Siz];
	int vis[Siz], tag[Siz];
	
	void init() {
		memset(head, 0, sizeof(head));
		cnt = 0;
	}
	
	void change(int _S, int _T, Ty _inf) {
		S = _S, T = _T, inf = _inf;
	}
	
	int gt(int x) {return x + (x & 1 ? 1 : -1);}
	 
	void add(int u, int v, Ty w, Ty c) {
		e[++cnt] = {v, head[u], w, c};
		head[u] = cnt;
	}
	
	void add_edge(int u, int v, Ty w, Ty c) {
		add(u, v, w, c);
		add(v, u, 0, -c);
	}
	
	void add_Edge(int u, int v, Ty w, Ty c) {
		add_edge(u, v, w, c);
		add_edge(v, u, w, c);
	}
	
	bool bfs() {
		memset(dis, 0x3f, sizeof(dis));
		Ty qwq = dis[0];
		memset(vis, 0, sizeof(vis));
		memset(tag, 0, sizeof(tag));
		dis[S] = 0;
		now[S] = head[S];
		vis[S] = 1;
		queue <int> q;
		q.push(S);
		//orz;
		while (!q.empty()) {
			int x = q.front();
			q.pop();
			vis[x] = 0;
			//cout << x << endl;
			for (int i = head[x]; i; i = e[i].nxt) {
				int v = e[i].to;
				if (dis[v] > dis[x] + e[i].cost && e[i].w > 0) {
					dis[v] = dis[x] + e[i].cost;
					now[v] = head[v];
					if (!vis[v]) vis[v] = 1, q.push(v);
				}
			}
		}
		return dis[T] != qwq;
	}
	
	Ty ans;
	
	Ty dfs(int x, Ty flow) {
		if (x == T) {
			ans += flow * dis[T];
			return flow;
		}
		tag[x] = 1;
		Ty sum = 0;
		for (int i = now[x]; i; i = e[i].nxt) {
			int v = e[i].to;
			now[x] = i;
			if (!tag[v] && dis[v] == dis[x] + e[i].cost && e[i].w > 0) {
				Ty tmp = dfs(v, min(e[i].w, flow - sum));
				sum += tmp;
				e[i].w -= tmp;
				e[gt(i)].w += tmp;
				if (sum == flow) break;
			}
		}
		if (sum == flow) tag[x] = 0;
		return sum;
	}
	
	Ty dinic() {
		ans = 0;
		Ty sum = 0;
		while (bfs()) sum += dfs(S, inf);
		cout << ans << endl;
		return sum;
	}
};

Graph <long long, 100005> G;

int n, m, s, t;

signed main() {
//	cin >> n >> m >> s;
//	G.change(0, n + 1, 1e9);
//	for (int i = 1, u; i <= n; i++) {
//		cin >> u;
//		G.add_edge(i, G.T, u, 0);
//	}
//	for (int i = 1, d; i <= n; i++) {
//		cin >> d;
//		G.add_edge(G.S, i, G.inf, d);
//	}	
//	for (int i = 1; i < n; i++) G.add_edge(i, i + 1, G.S, m);
//	printf("%d", G.dinic());
	cin >> n >> m >> s >> t;
	G.change(s, t, 1e18);
	for (int i = 1, u, v, w, c; i <= m; i++) {
		cin >> u >> v >> w >> c;
		G.add_edge(u, v, w, c);
	}
	cout << G.dinic() << ' ' << G.ans;
	return 0;
}

如图，此时本人的代码跑板子会输出 50 0

题目是这个 qwq

而如果换成如下：

#include <bits/stdc++.h>

using namespace std;

#define orz puts("---------------------")

template <typename Ty, int Siz>
struct Graph {
	struct Edge {
		int to, nxt;
		Ty w, cost;
	} e[Siz << 1];
	
	int head[Siz], now[Siz], cnt;
	int S, T;
	Ty inf;
	Ty dis[Siz];
	int vis[Siz], tag[Siz];
	
	void init() {
		memset(head, 0, sizeof(head));
		cnt = 0;
	}
	
	void change(int _S, int _T, Ty _inf) {
		S = _S, T = _T, inf = _inf;
	}
	
	int gt(int x) {return x + (x & 1 ? 1 : -1);}
	 
	void add(int u, int v, Ty w, Ty c) {
		e[++cnt] = {v, head[u], w, c};
		head[u] = cnt;
	}
	
	void add_edge(int u, int v, Ty w, Ty c) {
		add(u, v, w, c);
		add(v, u, 0, -c);
	}
	
	void add_Edge(int u, int v, Ty w, Ty c) {
		add_edge(u, v, w, c);
		add_edge(v, u, w, c);
	}
	
	bool bfs() {
		memset(dis, 0x3f, sizeof(dis));
		Ty qwq = dis[0];
		memset(vis, 0, sizeof(vis));
		memset(tag, 0, sizeof(tag));
		dis[S] = 0;
		now[S] = head[S];
		vis[S] = 1;
		queue <int> q;
		q.push(S);
		//orz;
		while (!q.empty()) {
			int x = q.front();
			q.pop();
			vis[x] = 0;
			//cout << x << endl;
			for (int i = head[x]; i; i = e[i].nxt) {
				int v = e[i].to;
				if (dis[v] > dis[x] + e[i].cost && e[i].w > 0) {
					dis[v] = dis[x] + e[i].cost;
					now[v] = head[v];
					if (!vis[v]) vis[v] = 1, q.push(v);
				}
			}
		}
		return dis[T] != qwq;
	}
	
	Ty ans = 0;
	
	Ty dfs(int x, Ty flow) {
		if (x == T) {
			ans += flow * dis[T];
			return flow;
		}
		tag[x] = 1;
		Ty sum = 0;
		for (int i = now[x]; i; i = e[i].nxt) {
			int v = e[i].to;
			now[x] = i;
			if (!tag[v] && dis[v] == dis[x] + e[i].cost && e[i].w > 0) {
				Ty tmp = dfs(v, min(e[i].w, flow - sum));
				sum += tmp;
				e[i].w -= tmp;
				e[gt(i)].w += tmp;
				if (sum == flow) break;
			}
		}
		if (sum == flow) tag[x] = 0;
		return sum;
	}
	
	pair<Ty, Ty> dinic() {
		ans = 0;
		Ty sum = 0;
		while (bfs()) sum += dfs(S, inf);
		return {sum, ans};
	}
};

Graph <long long, 100005> G;

int n, m, s, t;

signed main() {
//	cin >> n >> m >> s;
//	G.change(0, n + 1, 1e9);
//	for (int i = 1, u; i <= n; i++) {
//		cin >> u;
//		G.add_edge(i, G.T, u, 0);
//	}
//	for (int i = 1, d; i <= n; i++) {
//		cin >> d;
//		G.add_edge(G.S, i, G.inf, d);
//	}	
//	for (int i = 1; i < n; i++) G.add_edge(i, i + 1, G.S, m);
//	printf("%d", G.dinic());
	cin >> n >> m >> s >> t;
	G.change(s, t, 1e18);
	for (int i = 1, u, v, w, c; i <= m; i++) {
		cin >> u >> v >> w >> c;
		G.add_edge(u, v, w, c);
	}
	pair<long long, long long> qwq = G.dinic();
	cout << qwq.first << ' ' << qwq.second;
	return 0;
}

输出的就是正确的答案 50 280

但是我觉得这两种写法有不同吗？第一种为什么会寄？