Submission #838910

#	Time	Username	Problem	Language	Result	Execution time	Memory
838910		nnin	Dreaming (IOI13_dreaming)	C++14	0 / 100	36 ms	15688 KiB

dreaming

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

vector<pair<int, int>> adj[100005];
vector<int> group[100005];
int maxdis[100005], n;
bool vis[100005];

int dsu[100005];
int par(int x) {
    if(dsu[x]==x) return x;
    return dsu[x] = par(dsu[x]);
}

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

int mnGroup(int i) {
    int last = n;
    for(int j=1;j<group[i].size();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 ret = INT_MAX;
    for(int mxdis:group[i]) {
        ret = min(ret, maxdis[mxdis]);
    }
    return ret;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    n = N;
    for(int i=0;i<N;i++) dsu[i] = i;
    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]});
        dsu[par(A[i])] = par(B[i]);
    }
    for(int i=0;i<N;i++) group[par(i)].push_back(i);
    int mx = -1, mx2 = -1;
    for(int i=0;i<N;i++) {
        if(group[i].empty()) continue;
        int mn = mnGroup(i);
        if(mn >= mx) {
            mx2 = mx;
            mx = mn;
        } else if(mn > mx2) {
            mx2 = mn;
        }
    }
    if(mx2==-1) return mx;
    return mx+mx2+L;
}

Compilation message (stderr)

dreaming.cpp: In function 'int mnGroup(int)':
dreaming.cpp:28:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for(int j=1;j<group[i].size();j++) {
      |                 ~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23