模板里这个地方推荐加一个括号，不然有的编译器会有问题
#include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <vector> #include <queue> using namespace std; const int maxn = 20005; const int INF = 0x3f3f3f3f; struct Edge { int to, cap, rev; Edge(int x=0, int y=0, int z=0) : to(x), cap(y), rev(z) {} }; vector<Edge> G[maxn]; int level[maxn], iter[maxn]; void addedge(int u, int v, int cap) { G[u].push_back(Edge(v, cap, G[v].size())); G[v].push_back(Edge(u, 0, G[u].size()-1)); } void bfs(int s) { memset(level, -1, sizeof(level)); queue<int> q; level[s] = 0; q.push(s); while (!q.empty()) { int v = q.front(); q.pop(); for (int i = 0; i < G[v].size(); i++) { Edge &e = G[v][i]; if (e.cap > 0 && level[e.to] < 0) { level[e.to] = level[v] + 1; q.push(e.to); } } } } int dfs(int v, int t, int f) { if (v == t) return f; for (int &i = iter[v]; i < G[v].size(); i++) { Edge &e = G[v][i]; if (e.cap > 0 && level[v] < level[e.to]) { int d = dfs(e.to, t, min(f, e.cap)); if (d > 0) { e.cap -= d; G[e.to][e.rev].cap += d; return d; } } } return 0; } int max_flow(int s, int t) { int flow = 0; while (true) { bfs(s); if (level[t] < 0) return flow; memset(iter, 0, sizeof(iter)); int f; while ((f = dfs(s, t, INF)) > 0) flow += f; } } int n, m; int main() { scanf("%d %d", &n, &m); int a, b, cost; int s = n, t = n+1; for (int i = 0; i < n; i++) { scanf("%d %d", &a, &b); addedge(i, t, a); addedge(s, i, b); } for (int i = 0; i < m; i++) { scanf("%d %d %d", &a, &b, &cost); addedge(a-1, b-1, cost); addedge(b-1, a-1, cost); } printf("%d\n", max_flow(s, t)); return 0; }