Submission #469121

#	Time	Username	Problem	Language	Result	Execution time	Memory
469121		Carmel_Ab1	Dynamic Diameter (CEOI19_diameter)	C++17	42 / 100	5074 ms	43036 KiB

diameter

#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//using namespace __gnu_pbds;
using namespace std;

typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<pl> vpl;
typedef vector<ld> vld;
typedef pair<ld, ld> pld;

//typedef tree<ll, null_type, less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
template<typename T>
ostream &operator<<(ostream &os, vector<T> &a) {
    os << "[";
    for (int i = 0; i < ll(a.size()); i++) { os << a[i] << ((i != ll(a.size() - 1) ? " " : "")); }
    os << "]\n";
    return os;
}

#define all(x) x.begin(),x.end()
#define YES out("YES")
#define NO out("NO")
#define out(x){cout << x << "\n"; return;}
#define GLHF ios_base::sync_with_stdio(false); cin.tie(NULL)
#define print(x){for(auto ait:x) cout << ait << " "; cout << "\n";}
#define pb push_back
#define umap unordered_map

template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
    is >> p.first >> p.second;
    return is;
}

template<typename T1, typename T2>
ostream &operator<<(ostream &os, pair<T1, T2> &p) {
    os << "" << p.first << " " << p.second << "";
    return os;
}

void usaco(string taskname) {
    string fin = taskname + ".in";
    string fout = taskname + ".out";
    const char *FIN = fin.c_str();
    const char *FOUT = fout.c_str();
    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);
}

template<typename T>
void read(vector<T> &v) {
    int n = v.size();
    for (int i = 0; i < n; i++)
        cin >> v[i];
}

template<typename T>
vector<T> UNQ(vector<T> a) {
    vector<T> ans;
    for (T t:a)
        if (ans.empty() || t != ans.back())
            ans.push_back(t);
    return ans;
}

ll ceil(ll a, ll b) {
    ll ans = a / b;
    if (a % b)ans++;
    return ans;
}

ld log(ld a, ld b) { return log(b) / log(a); }

ll power(ll base, ll exp, ll M = 1e18) {//(base^exp)%M
    ll ans = 1;
    while (exp) {
        if (exp % 2 == 1)ans = ((ans % M) * (base % M)) % M;
        base = ((base % M) * (base % M)) % M;
        exp /= 2;
    }
    return ans;
}

string to_base(int n, int new_base) {
    string s;
    int nn = n;
    while (nn) {
        s += to_string(nn % new_base);
        nn /= new_base;
    }
    reverse(all(s));
    return s;
}

ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
    ll x = (a / gcd(a, b));
    return b * x;
}

vl generate_array(ll n, ll mn = 1, ll mx = 1e18 + 1) {
    if (mx == 1e18 + 1)
        mx = n;
    vl ans(n);
    for (int i = 0; i < n; i++)
        ans[i] = (mn + rand() % (mx - mn + 1));
    return ans;
}

string substr(string s, int l, int r) {
    string ans;
    for (int i = l; i <= r; i++)
        ans += s[i];
    return ans;
}


void solve();

int main() {
    GLHF;
    int t = 1;
    //cin >> t;
    while (t--)
        solve();
}
vvi g;
umap<ll,umap<ll,ll>>c;
vl par,dep,mx,diam;
multiset<ll>s;
void dfs(int src,int p){
    par[src]=p;
    if(p!=-1)
        dep[src]=dep[p]+1;
    ll mx1=-1,mx2=-1;
    vl v;
    for(int nbr:g[src])
        if(nbr!=par[src]){
            dfs(nbr,src);
            mx[src]=max(mx[src],mx[nbr]+c[src][nbr]);
            v.pb(mx[nbr]+c[src][nbr]);
        }
    sort(all(v));
    if(v.size()>1){
        mx1=v[v.size()-1],mx2=v[v.size()-2];
        diam[src]=mx1+mx2;
        s.insert(diam[src]);
    }
}

void calc(ll src){
    int n=g.size()-1;
    while(src!=-1){
        mx[src]=0;
        for(int nbr:g[src])
            if(nbr!=par[src])
                mx[src]=max(mx[src],mx[nbr]+c[src][nbr]);
        ll mx1=-1,mx2=-1;
        if(s.count(diam[src]))
            s.erase(s.find(diam[src]));
        vl v;
        for(int nbr:g[src])
            if(nbr!=par[src]){
                v.pb(mx[nbr]+c[src][nbr]);
            }
        sort(all(v));
        if(v.size()>1){
            mx1=v[v.size()-1],mx2=v[v.size()-2];
            diam[src]=mx1+mx2;
            s.insert(diam[src]);
        }
        src=par[src];
    }


}
void solve() {
    ll n,q,maxw;
    cin >> n >> q >> maxw;
    g.resize(n+1);

    vpl E(n-1);
    vi deg(n+1);
    int rt=1;
    for(int i=0; i<n-1; i++){
        ll u,v,w;
        cin >> u >> v >> w;
        g[u].pb(v);
        g[v].pb(u);
        c[u][v]=c[v][u]=w;
        E[i]={u,v};
        deg[u]++,deg[v]++;
        if(deg[u]>1)
            rt=u;
        if(deg[v]>1)
            rt=v;
    }

    dep.resize(n+1);
    par.resize(n+1,-1);
    mx.resize(n+1);
    diam.resize(n+1);
    if(n!=2)
        dfs(rt,-1);

    ll ans=0;
    while(q--){
        ll d,w;
        cin >> d >> w;
        d=(ans+d)%(n-1);
        w=(ans+w)%maxw;
        ll v=E[d].first,u=E[d].second;
        c[u][v]=c[v][u]=w;
        if(n==2){
            cout << w << "\n";
            continue;
        }
        calc((dep[u]<dep[v])?u:v);
        cout << (ans=*s.rbegin()) << "\n";

    }
}

Compilation message (stderr)

diameter.cpp: In function 'void calc(ll)':
diameter.cpp:167:9: warning: unused variable 'n' [-Wunused-variable]
  167 |     int n=g.size()-1;
      |         ^
diameter.cpp: In function 'void usaco(std::string)':
diameter.cpp:56:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     freopen(FIN, "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~
diameter.cpp:57:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |     freopen(FOUT, "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 0 / 7
• Subtask 4: 18 / 18
• Subtask 5: 0 / 24
• Subtask 6: 0 / 27