Submission #770004

#	Time	Username	Problem	Language	Result	Execution time	Memory
770004		vjudge1	Paths (RMI21_paths)	C++17	0 / 100	208 ms	23500 KiB

Main

#include <bits/stdc++.h>
#define ve vector
#define vi vector<int>
#define vii vector<ii>
#define ii pair<int,int>
#define fi first
#define se second
#define ll long long
#define INF 1e9+7
#define pb push_back
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag,
    tree_order_statistics_node_update>;
const int MOD = 1e9+7;
const int nax = 2e5+5;
const int l = 25;
void readio(){
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
}
ve<pair<int,ll>> adj[nax];
bool vis[nax];
ll mxs[nax], dep[nax];
int up[nax][l];
int timer = 0, tin[nax], tout[nax];
ll dfs(int u, int p){
    tin[u] = ++timer;
    up[u][0] = p;
    for (int i = 1; i <= l; ++i)
        up[u][i] = up[up[u][i-1]][i-1];

    for(auto x : adj[u]){
        if(x.fi == p) continue;
        dep[x.fi] = dep[u]+x.se;
        if(!vis[x.fi]) mxs[u] = max(mxs[u], dfs(x.fi,u)+x.se);
        else  mxs[u] = max(mxs[u], dfs(x.fi, u));
    }
    tout[u] = ++timer;
    //cout << u << " " << mx << endl;
    return mxs[u];
}
bool ass(int u, int p, ll path, ll mx){
    if(path == mx) return 1;
    for(auto x : adj[u]){
        if(x.fi == p) continue;
        ll cur = path;
        if(!vis[x.fi]) cur += x.se;
        if(ass(x.fi,u,cur,mx)){
            vis[x.fi] = 1;
            return 1;
        }
    }
    return 0;
}
ii ans;
bool isAnc(int u, int v){
    return (tin[u] <= tin[v] && tout[v] <= tout[u]);
}

int lca(int u, int v)
{
    if (isAnc(u, v))
        return u;
    if (isAnc(v, u))
        return v;
    for (int i = l; i >= 0; --i) {
        if (!isAnc(up[u][i], v))
            u = up[u][i];
    }
    return up[u][0];
}
ll distance(int a, int b){
    int c = lca(a,b);
    //cout << a << " " << dep[a] << " " << b << " " << dep[b] << endl;
    return (dep[a]+dep[b]-2*dep[c]);
}
void diam(int u, int p, int cur){
    if(ans.fi < cur) ans.fi = cur, ans.se = u;
    for(auto x : adj[u]){
        if(x.fi == p) continue;
        diam(x.fi, u, cur+x.se);
    }
}
int main()
{
    optimise;
    int n, k;
    cin >> n >> k;
    for(int i = 0; i < n-1; i++){
        int a,b,c;
        cin >> a >> b >> c;
        a--,b--;
        adj[a].pb({b,c});
        adj[b].pb({a,c});
    } 
    if(k == 1){
        dfs(0,0);
        int a,b;
        ans = {0,0};
        diam(0,0,0);
        a = ans.se;
        ans = {0,0};
        diam(a,a,0);
        b = ans.se;
        for (int i = 0; i < n; ++i)
        {
            //cout << distance(b,i) << " " << distance(a,i) << endl;
            cout << max(distance(a,i), distance(b,i)) << endl;
        }
        return 0;
    }
    for (int i = 0; i < n; ++i)
    {
        ll mx = 0;
        memset(vis,0, sizeof vis);
        for (int j = 0; j < k; ++j)
        {
            ll cur = dfs(i,i);
            mx += cur;
            ass(i,i, 0, cur);
        }
        cout << mx << endl;
    }
    
}

Compilation message (stderr)

Main.cpp: In function 'void readio()':
Main.cpp:23:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:24:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp: In function 'long long int dfs(int, int)':
Main.cpp:36:18: warning: iteration 24 invokes undefined behavior [-Waggressive-loop-optimizations]
   36 |         up[u][i] = up[up[u][i-1]][i-1];
      |         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Main.cpp:35:23: note: within this loop
   35 |     for (int i = 1; i <= l; ++i)
      |                     ~~^~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 11
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 12
• Subtask 6: 0 / 32