Submission #838927

#	Time	Username	Problem	Language	Result	Execution time	Memory
838927		nnin	Dreaming (IOI13_dreaming)	C++14	100 / 100	74 ms	18112 KiB

dreaming

#include "dreaming.h"
#include<bits/stdc++.h>
#define pii pair<int, int>
#define f first
#define s second
using namespace std;

vector<pii> adj[100005];
vector<int> group[100005];
int maxdis[100005];
bool vis[100005], vis0[100005];

void dfs(int cur, int prev, int dis) {
    maxdis[cur] = max(maxdis[cur], dis);
    for(pii next:adj[cur]) {
        if(prev==next.f) continue;
        dfs(next.f, cur, dis+next.s);
    }
}

void inGroup(int root, int cur, int prev) {
    group[root].push_back(cur);
    vis0[cur] = 1;
    for(pii next:adj[cur]) {
        if(next.f==prev) continue;
        inGroup(root, next.f, cur);
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    for(int i=0;i<M;i++) {
        adj[A[i]].push_back({B[i], T[i]});
        adj[B[i]].push_back({A[i], T[i]});
    }
    for(int i=0;i<N;i++) {
        if(vis0[i]) continue;
        inGroup(i, i, -1);
    }
    int mx = -1, mx2 = -1, mx3 = -1, ans = 0;
    for(int i=0;i<N;i++) {
        if(group[i].empty()) continue;
        int last = N;
        for(int j=0;j<3;j++) {
            int st = N;
            for(int node:group[i]) {
                if(!vis[node] && maxdis[node]>=maxdis[st] && maxdis[node]>=maxdis[last]) st = node;
            }
            if(st==N) break;
            dfs(st, -1, 0);
            vis[st] = 1;
            last = st;
        }
        int mn = INT_MAX;
        for(int mxdis:group[i]) {
            mn = min(mn, maxdis[mxdis]);
            ans = max(ans, maxdis[mxdis]);
        }
        if(mn >= mx) {
            mx3 = mx2;
            mx2 = mx;
            mx = mn;
        } else if(mn >= mx2) {
            mx3 = mx2;
            mx2 = mn;
        } else if(mn > mx3) {
            mx3 = mn;
        }
    }
    if(mx3!=-1) {
        ans = max(ans, mx3+mx2+L+L);
    }
    if(mx2!=-1) {
        ans = max(ans, mx+mx2+L);
    }
    return ans;
}

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