Download Speed

#include <climits>
#include <cmath>
#include <iostream>
#include <vector>

// Debug printing
#ifdef DEBUG
#define deb(fmt, args...) printf("DEBUG: %d: " fmt, __LINE__, ##args)
#else
#define deb(fmt, args...)
#endif

using namespace std;
using ll = long long;

void print_array(vector<int> in, const string title = "Vector")
{
	cout << title << " [\n";
	for (const auto &el : in) {
		cout << el << " ";
	}
	cout << "\n] END\n";
}

void print_matrix(vector<vector<int> > in, const string title = "Matrix")
{
	cout << title << " [\n";
	for (unsigned int i = 0; i < in.size(); i++) {
		cout << "row " << i << ": ";
		for (unsigned int j = 0; j < in[i].size(); j++) {
			cout << in[i][j] << " ";
		}
		cout << "\n";
	}
	cout << "] END\n";
}

int target;
int found = true;
vector<int> path;
bool visited[500];

void dfs(int vert, vector<vector<int> > &adj, vector<vector<int> > &edges)
{
	if (found) {
		return;
	}
	if (visited[vert]) {
		return;
	};
	visited[vert] = true;
	if (vert == target) {
		found = true;
		return;
	}

	for (auto u : adj[vert]) {
		int b = edges[u][1];
		int c = edges[u][2];
		// deb("s: %d, a: %d, b: %d, c: %d\n", s, a, b, c);
		if (c > 0) {
			path.push_back(u); // Add edge to path
			dfs(b, adj, edges);
			if (found)
				return;
			path.pop_back(); // remove edge from path
		}
	}
}

int main(int argc, char *argv[])
{
	int n, m;
	cin >> n >> m;
	target = n;

	// each edge is of form (a, b, c)
	vector<vector<int> > edges(m + 1, vector<int>(3));
	for (int i = 1; i < m + 1; i++) {
		cin >> edges[i][0] >> edges[i][1] >> edges[i][2];
	}

	// adjacent structure contains the edge indices that are adjacent to the
	// node
	vector<vector<int> > adj(n + 1, vector<int>());
	for (int j = 1; j < m + 1; j++) {
		adj[edges[j][0]].push_back(j);
	}

	// print_matrix(edges, "edges");
	// print_matrix(adj, "adjacent");

	ll speed = 0;
	while (found) {
		found = false;
		for (int i = 0; i < n + 1; i++)
			visited[i] = false;

		path.clear();
		dfs(1, adj, edges);
		// print_array(path, "path");
		if (found) {
			int residual = INT_MAX;

			// find residual capacity of the path
			for (auto e : path) {
				vector<int> edge = edges[e];
				if (edge[2] < residual)
					residual = edge[2];
			}
			// deb("res: %d\n", residual);
			speed += residual;

			// update flows
			for (auto e : path) {
				edges[e][2] -= residual;
			}
		}
	}

	cout << speed << "\n";

	return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER