Submission #396713

#	Time	Username	Problem	Language	Result	Execution time	Memory
396713		Sorting	Training (IOI07_training)	C++17	0 / 100	3 ms	460 KiB

training

#include <bits/stdc++.h>

using namespace std;

const int N = 2000 + 3;
const int M = 5000 + 3;

int n, m;

vector<int> adj[N];
vector<array<int, 3>> e, e2;
vector<int> arr, dp;
int pos[N];

void dfs(int u, int p = -1){
    arr.push_back(u);
    pos[u] = (int)arr.size() - 1;

    for(int to: adj[u])
        if(to != p)
            dfs(to, u);
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;
    for(int i = 0; i < m; ++i){
        int a, b, c;
        cin >> a >> b >> c;
        if(!c){
            adj[a].push_back(b);
            adj[b].push_back(a);
        }
        else e.push_back({a, b, c});
    }

    dfs(1);

    for(int i = 0; i < e.size(); ++i){
        auto [a, b, c] = e[i];
        int new_a = pos[a];
        int new_b = pos[b];
        e[i] = {min(new_a, new_b), max(new_a, new_b), c};
    }

    int ans = 0;
    for(int i = 0; i < e.size(); ++i){
        auto [a, b, c] = e[i];
        if((b - a) & 1) ans += c;
        else e2.push_back({a, b, c});
    }

    sort(e2.begin(), e2.end());

    dp.resize(e2.size() + 1);
    dp[e2.size()] = 0;
    for(int i = (int)e2.size() - 1; i >= 0; --i){
        int next_idx = lower_bound(e2.begin(), e2.end(), array{e2[i][1], 0, 0}) - e2.begin();
        next_idx = max(next_idx, i + 1);
        dp[i] = max(dp[i + 1], e2[i][2] + dp[next_idx]);
    }

    ans -= dp[0];
    for(int i = 0; i < e2.size(); ++i)
        ans += e2[i][2];

    cout << ans << "\n";
}
/*
3 3
1 3 1
1 2 0
2 3 0
*/

Compilation message (stderr)

training.cpp: In function 'int main()':
training.cpp:41:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |     for(int i = 0; i < e.size(); ++i){
      |                    ~~^~~~~~~~~~
training.cpp:49:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |     for(int i = 0; i < e.size(); ++i){
      |                    ~~^~~~~~~~~~
training.cpp:66:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for(int i = 0; i < e2.size(); ++i)
      |                    ~~^~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 7
• Subtask 5: 0 / 9
• Subtask 6: 0 / 9
• Subtask 7: 0 / 9
• Subtask 8: 0 / 9
• Subtask 9: 0 / 9
• Subtask 10: 0 / 9
• Subtask 11: 0 / 9