Submission #770077

#	Time	Username	Problem	Language	Result	Execution time	Memory
770077		AmirElarbi	Paths (RMI21_paths)	C++14	36 / 100	1020 ms	1052 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 = 2000+5;
const int l = 25;
void readio(){
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
}
//segment Tree
ll lazy[nax*4];
pair<ll,int> st[nax*4];
ve<pair<ll,int>> leef;
void build(int v, int l, int r){
    if(l == r){
        st[v] = leef[l];
        lazy[v] = 0;
        return;
    }
    int md = (l+r)/2;
    build(v*2,l,md);
    build(v*2+1,md+1,r);
    st[v] = max(st[v*2], st[v*2+1]);
    lazy[v] = 0;
}
void push(int v){
    if(!lazy[v]) return;
    st[v*2].fi += lazy[v];
    st[v*2+1].fi += lazy[v];
    lazy[v*2] += lazy[v];
    lazy[v*2+1] += lazy[v];
    lazy[v] = 0;
}
void update(int v, int l, int r, int i, int j, ll val){
    if(r < i || l > j) return;
    if(i <= l && r <= j){
        st[v].fi += val;
        lazy[v] += val;
        return;
    }
    push(v);
    int md = (l+r)/2;
    update(v*2,l,md,i,j,val);
    update(v*2+1,md+1,r,i,j,val);
    st[v] = max(st[v*2], st[v*2+1]);
}
ve<pair<int,ll>> adj[nax];
bool vis[nax];
ll dep[nax], w[nax];
int up[nax][l+5];
int timer = 0, root, tin[nax], tout[nax], cnt = 0, tstin[nax], tstout[nax];
void dfs(int u, int p, ll path){
    tin[u] = ++timer;
    tstin[u] = cnt;
    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;
        w[x.fi] = x.se;
        dfs(x.fi,u,path+x.se);
    }
    if(adj[u].size() == 1 && u!=root){
        leef.pb({path, u});
        cnt++;
    }
    tstout[u] = cnt;
    tout[u] = ++timer;
}
void ass(int u){
    if(vis[u] || u == root) return;
    update(1, 0, cnt-1, tstin[u],tstout[u]-1, -w[u]);
    vis[u] = 1;
    ass(up[u][0]);
}



// Subtask 5
pair<ll,int> 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, ll 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(0,0,0);
        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 << max(distance(a,i), distance(b,i)) << endl;
        }
        return 0;
    }
    for (int i = 0; i < n; ++i)
    {
        memset(vis,0,sizeof vis);
        ll mx = 0;
        root = i;
        cnt = 0;
        timer = 0;
        leef.clear();
        dfs(i,i,0);
        build(1,0,cnt-1);
        //for(auto x : leef) cout << x.fi << " " << x.se << endl;
        //cout << cnt << endl;
        for (int j = 0; j < k; ++j)
        {
            pair<ll,int> a = st[1];
            //cout <<'\t' << a.fi << " " << a.se  << endl;
            mx += a.fi;
            ass(a.se);
        }
        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);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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