CSES - Aalto Competitive Programming 2024 - wk7 Homework - Results
Submission details
Task:Download Speed
Sender:bielaltes
Submission time:2024-10-15 19:12:06 +0300
Language:C++ (C++11)
Status:READY
Result:
Test results
testverdicttime
#1ACCEPTED0.00 sdetails
#2ACCEPTED0.00 sdetails
#3--details
#4ACCEPTED0.00 sdetails
#50.00 sdetails
#6ACCEPTED0.01 sdetails
#7--details
#8ACCEPTED0.00 sdetails
#9ACCEPTED0.00 sdetails
#10ACCEPTED0.00 sdetails
#110.00 sdetails
#12ACCEPTED0.00 sdetails

Compiler report

input/code.cpp: In function 'int fordFulkerson(int, std::vector<std::vector<int> >&, std::vector<std::vector<int> >&, int, int)':
input/code.cpp:40:21: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   40 |     while (new_flow = bfs(capacity, adj, parent, source, sink)) {
      |            ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Code

#include <iostream>
#include <vector>
#include <queue>
#include <climits>
#include <cstring>

using namespace std;

bool bfs(const vector<vector<int>>& capacity, vector<vector<int>>& adj, vector<int>& parent, int source, int sink) {
    fill(parent.begin(), parent.end(), -1);
    parent[source] = source;
    queue<pair<int, int>> q;
    q.push({source, INT_MAX});

    while (!q.empty()) {
        int cur = q.front().first;
        int flow = q.front().second;
        q.pop();

        for (int next : adj[cur]) {
            if (parent[next] == -1 && capacity[cur][next] > 0) {
                parent[next] = cur;
                int new_flow = min(flow, capacity[cur][next]);
                if (next == sink) {
                    return new_flow;
                }
                q.push({next, new_flow});
            }
        }
    }

    return 0;
}

int fordFulkerson(int n, vector<vector<int>>& capacity, vector<vector<int>>& adj, int source, int sink) {
    int max_flow = 0;
    vector<int> parent(n);

    int new_flow;
    while (new_flow = bfs(capacity, adj, parent, source, sink)) {
        max_flow += new_flow;
        int cur = sink;
        while (cur != source) {
            int prev = parent[cur];
            capacity[prev][cur] -= new_flow;
            capacity[cur][prev] += new_flow;
            cur = prev;
        }
    }

    return max_flow;
}

int main() {
    int n, m;
    cin >> n >> m;

    vector<vector<int>> capacity(n, vector<int>(n, 0));
    vector<vector<int>> adj(n);

    for (int i = 0; i < m; ++i) {
        int a, b, c;
        cin >> a >> b >> c;
        --a; --b; // Convert to 0-based index
        capacity[a][b] += c;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    int source = 0;
    int sink = n - 1;

    cout << fordFulkerson(n, capacity, adj, source, sink) << endl;

    return 0;
}

Test details

Test 1

Verdict: ACCEPTED

input
4 3
1 2 5
2 3 3
3 4 6

correct output
3

user output
3

Test 2

Verdict: ACCEPTED

input
4 5
1 2 1
1 3 1
2 3 1
2 4 1
...

correct output
2

user output
2

Test 3

Verdict:

input
4 5
1 2 1000000000
1 3 1000000000
2 3 1
2 4 1000000000
...

correct output
2000000000

user output
(empty)

Test 4

Verdict: ACCEPTED

input
2 1
2 1 100

correct output
0

user output
0

Test 5

Verdict:

input
2 1000
1 2 1000000000
1 2 1000000000
1 2 1000000000
1 2 1000000000
...

correct output
1000000000000

user output
0

Test 6

Verdict: ACCEPTED

input
500 998
1 2 54
1 3 59
1 4 83
2 5 79
...

correct output
60

user output
60

Test 7

Verdict:

input
500 998
1 2 530873053
1 3 156306296
1 4 478040476
3 5 303609600
...

correct output
1093765123

user output
(empty)

Test 8

Verdict: ACCEPTED

input
2 1
1 2 1

correct output
1

user output
1

Test 9

Verdict: ACCEPTED

input
4 5
1 2 3
2 4 2
1 3 4
3 4 5
...

correct output
6

user output
6

Test 10

Verdict: ACCEPTED

input
4 5
1 2 1
1 3 2
3 2 1
2 4 2
...

correct output
3

user output
3

Test 11

Verdict:

input
10 999
1 2 1000000000
1 2 1000000000
1 2 1000000000
1 2 1000000000
...

correct output
111000000000

user output
0

Test 12

Verdict: ACCEPTED

input
7 9
1 2 1
1 3 1
1 4 1
2 5 1
...

correct output
2

user output
2