acwing::acwing851 命名空间参考

1. spfa求最短路

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函数
int	main (istream &cin, ostream &cout)
	TEST (acwing851, case1)

详细描述

1. spfa求最短路

函数说明

main()

int acwing::acwing851::main	(	istream &	cin,
		ostream &	cout )

在文件 acwing.cpp 第 7232 行定义.

                                              {
            int n;
            int m;
            cin >> n >> m;
            vector<unordered_map<int, int>> g(n + 1);
            vector reachable(n + 1, false);
            vector shortest(n + 1, 0x3f3f3f);
            for(int i = 0; i < m; i++) {
                int x;
                int y;
                int z;
                cin >> x >> y >> z;
                if(g[x][y] == 0) {
                    g[x][y] = z;
                } else {
                    g[x][y] = min(g[x][y], z);
                }
            }
            queue<int> q;
            unordered_set<int> us;
            us.insert(1);
            q.push(1);
            shortest[1]  = 0;
            reachable[1] = true;
            while(!q.empty()) {
                int node = q.front();
                q.pop();
                us.erase(node);
                for(auto [next_node, d]: g[node]) {
                    reachable[next_node] = true;
                    if(shortest[next_node] > shortest[node] + d) {
                        shortest[next_node] = shortest[node] + d;
                        if(!us.contains(next_node)) {
                            q.push(next_node);
                            us.insert(next_node);
                        }
                    }
                }
            }
            if(!reachable[n]) {
                cout << "impossible";
            } else {
                cout << shortest[n];
            }
            return 0;
        }

被这些函数引用 TEST().

TEST()

acwing::acwing851::TEST	(	acwing851	,
		case1	)

在文件 acwing_test.cpp 第 3399 行定义.

                               {
            istringstream in("3 3\n"
                             "1 2 5\n"
                             "2 3 -3\n"
                             "1 3 4");
            auto out = ostringstream();
            main(in, out);
            const auto ans = out.str();
            ASSERT_EQ("2", ans);
        }

引用了 main().