Submission #1275497

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275497		quanduongxuan12	Dreaming (IOI13_dreaming)	C++20	100 / 100	46 ms	18656 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
#define name "dreaming"
#define MAXN 100005
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const int INF=1e9;
const int MOD=1e9+7;
void add(int &u, int v){
    u+=v;
    if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
    u-=v;
    if (u<0) u+=MOD;
}
void minimize(int &u, int v){
    u=min(u,v);
}
void maximize(int &u, int v){
    u=max(u,v);
}
long long Rand(long long l, long long r){
    ll tmp=0;
    FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
    return l+tmp%(r-l+1);
}
ii Max[MAXN],res[MAXN];
vector<ii> adj[MAXN];
int depth[MAXN],high[MAXN];
bool visited[MAXN];
vector<ii> vec;
void dfs0(int u, int p){
    visited[u]=1;
    Max[u]={0,0};
    for (ii pairs:adj[u]){
        int v=pairs.fs;
        int w=pairs.sc;
        if (v==p) continue;
        dfs0(v,u);
        maximize(high[u],high[v]+w);
        if (high[v]+w>Max[u].fs){
            Max[u].sc=Max[u].fs;
            Max[u].fs=high[v]+w;
        }
        else maximize(Max[u].sc,high[v]+w);
    }
}
int diam;
void dfs1(int u, int p){
    res[u]=Max[u];
    if (depth[u]>res[u].fs){
        res[u].sc=res[u].fs;
        res[u].fs=depth[u];
    }
    else maximize(res[u].sc,depth[u]);
    if (res[u].fs+res[u].sc>diam){
        diam=res[u].fs+res[u].sc;
        vec.back()=res[u];
    }
    else if (res[u].fs+res[u].sc==diam){
        if (vec.back().fs>res[u].fs) vec.back()=res[u];
    }
    for (ii pairs:adj[u]){
        int v=pairs.fs;
        int w=pairs.sc;
        if (v==p) continue;
        if (Max[u].fs==Max[v].fs+w){
            depth[v]=max(depth[u],Max[u].sc)+w;
        }
        else{
            depth[v]=max(depth[u],Max[u].fs)+w;
        }
        dfs1(v,u);
    }
}
bool cmp(const ii& X, const ii& Y){
    return X.fs>Y.fs;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    FOR(i,1,M){
        int x=A[i-1],y=B[i-1],w=T[i-1];
        ++x;
        ++y;
        adj[x].pb({y,w});
        adj[y].pb({x,w});
    }
    int kq=0;
    FOR(i,1,N) if (!visited[i]){
        dfs0(i,0);
        diam=0;
        vec.pb({0,0});
        dfs1(i,0);
        maximize(kq,diam);
    }
    sort(all(vec),cmp);
    if (vec.size()>=2) maximize(kq,vec[0].fs+vec[1].fs+L);
    if (vec.size()>=3) maximize(kq,vec[2].fs+vec[1].fs+2*L);
    return kq;
}

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23