Codeforces div2-C

1 
using namespace std;

vector<vector<int>> adj;
bool visited[20006];
int height[20006];
void dfs(int node,int level)
{
    visited[node]=true;
    for(int i=0;i<adj[node].size();i++)
    {
        if(!visited[adj[node][i]])
        {
            height[adj[node][i]]=height[node]+1;
            dfs(adj[node][i],height[adj[node][i]]);
        }
    }
}

int main()
{
    int n,k;
    cin>>n>>k;
    for(int i=1;i<=n;i++)
    {
        height[i]=0;
        visited[i]=false;
    }
    for(int i=0;i<n-1;i++)
    {
        int x,y;
        cin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    dfs(1,0);
    sort(height,height+n);
    int i=n-1;
    int hap=0;
    while(k>0)
    {
        hap+=height[i];
        i--;
        k--;
    }
    cout<<hap<<"\n";

}

why this approach is wrong?
I am trying to store the height of each level in an array and sorting it and calculating the happiness!

2

your code will not give correct output for the first sample testcase if k=5,in this case answer should be 7 but a/t your logic it will give 8,this is because if you select some non leaf as industry city,then happiness of all the child of this node will decreases by 1 which you are not considering.

1 Like