Submission #978063

#	Time	Username	Problem	Language	Result	Execution time	Memory
978063		yeediot	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	381 ms	58112 KiB

diameter

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
    int a,b;
    int operator()(const int x)const{
        return a*x+b;
    }
};
bool check(line l1,line l2,line l3){
    return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
const int mxn=1e5+5;
const int inf=-1e18;
int n, q, w, ord[2*mxn], timer, in[mxn], out[mxn], d[mxn];

vector<pair<int,int>>adj[mxn];
vector<tuple<int,int,int>>edges;
struct segtree{
    struct node{
        int ijk,ij,jk,i,j,k;
    }seg[8*mxn];
    int tag[8*mxn];
    void build(int l,int r,int id){
        seg[id].ijk=seg[id].ij=seg[id].jk=seg[id].i=seg[id].j=seg[id].k=0;
        tag[id]=0;
        if(l==r){
            return;
        }
        int mm=l+r>>1;
        build(l,mm,id*2);
        build(mm+1,r,id*2+1);
    }
    void upd(int id,int v){
        seg[id].ij-=v;
        seg[id].jk-=v;
        seg[id].i+=v;
        seg[id].j-=2*v;
        seg[id].k+=v;
        tag[id]+=v;
    }
    void push(int id){
        upd(id*2,tag[id]);
        upd(id*2+1,tag[id]);
        tag[id]=0;
    }
    node merge(node a,node b){
        node res={inf,inf,inf,inf,inf,inf};
        res.ijk=max({a.ijk,b.ijk,a.i+b.jk,a.ij+b.k});
        res.ij=max({a.ij,b.ij,a.i+b.j});
        res.jk=max({a.jk,b.jk,a.j+b.k});
        res.i=max({a.i,b.i});
        res.j=max({a.j,b.j});
        res.k=max({a.k,b.k});
        return res;
    }
    void modify(int l,int r,int id,int ql,int qr,int v){
        if(qr<l or r<ql){
            return;
        }
        if(ql<=l and r<=qr){
            upd(id,v);
            return;
        }
        push(id);
        int mm=l+r>>1;
        modify(l,mm,id*2,ql,qr,v);
        modify(mm+1,r,id*2+1,ql,qr,v);
        seg[id]=merge(seg[id*2],seg[id*2+1]);
    }
    void modify(int l,int r,int v){
        modify(1,2*n-1,1,l,r,v);
    }
}tr;
void dfs(int v,int pa){
    ord[++timer]=v;
    in[v]=timer;
    for(auto [u,len]:adj[v]){
        if(u==pa){
            continue;
        }
        d[u]=d[v]+len;
        dfs(u,v);
        ord[++timer]=v;
    }
    out[v]=timer;
}
signed main(){
    setio();
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>q>>w;
    for(int i=1;i<n;i++){
        int a,b,c;
        cin>>a>>b>>c;
        adj[a].pb({b,c});
        adj[b].pb({a,c});
        edges.pb({a,b,c});
    }
    dfs(1,1);
    tr.build(1,2*n-1,1);
    for(int i=0;i+1<n;i++){
        auto &[a,b,c]=edges[i];
        if(d[a]>d[b]){
            swap(a,b);
        }
        tr.modify(in[b],out[b],c);
        debug(a,b,c,in[b],out[b]);
    }
    int prev=0;
    for(int i=0;i<q;i++){
        int f,s;
        cin>>f>>s;
        f=(f+prev)%(n-1);
        s=(s+prev)%w;
        auto &[a,b,c]=edges[f];
        int dif=s-c;
        c=s;
        tr.modify(in[b],out[b],dif);
        prev=tr.seg[1].ijk;
        cout<<prev<<'\n';
    }
}
 /*
 input:
 1 2 3 2 4 2 1
 */















 

Compilation message (stderr)

diameter.cpp: In member function 'void segtree::build(long long int, long long int, long long int)':
diameter.cpp:71:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   71 |         int mm=l+r>>1;
      |                ~^~
diameter.cpp: In member function 'void segtree::modify(long long int, long long int, long long int, long long int, long long int, long long int)':
diameter.cpp:107:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  107 |         int mm=l+r>>1;
      |                ~^~
diameter.cpp: In function 'void setIO(std::string)':
diameter.cpp:42:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diameter.cpp:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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