Submission #153816

#	Time	Username	Problem	Language	Result	Execution time	Memory
153816		popovicirobert	Dreaming (IOI13_dreaming)	C++14	100 / 100	158 ms	16336 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>

using namespace std;

const int INF = 2e9;
const int MAXN = (int) 1e5;

static vector < pair <int, int> > g[MAXN + 1];
static int dstA[MAXN + 1], dstB[MAXN + 1];
static bool vis[MAXN + 1], on_way[MAXN + 1];
static vector <int> nodes;

void dfs(int nod, int par, int *dst) {
    if(vis[nod] == 0) {
        nodes.push_back(nod);
    }
    vis[nod] = 1;
    for(auto it : g[nod]) {
        if(it.first != par) {
            dst[it.first] = dst[nod] + it.second;
            dfs(it.first, nod, dst);
        }
    }
}

int travelTime(int n, int m, int l, int A[], int B[], int T[]) {
    int i;
    for(i = 0; i < m; i++) {
        A[i]++, B[i]++;
        g[A[i]].push_back({B[i], T[i]});
        g[B[i]].push_back({A[i], T[i]});
    }

    vector <int> dst;
    int ans = 0;
    for(i = 1; i <= n; i++) {
        if(vis[i]) continue;

        nodes.clear();
        dfs(i, 0, dstA);
        int a = 0;
        for(auto it : nodes) {
            if(dstA[it] >= dstA[a]) {
                a = it;
            }
        }
        dstA[a] = 0;
        dfs(a, 0, dstA);

        int b = 0;
        for(auto it : nodes) {
            if(dstA[it] >= dstA[b]) {
                b = it;
            }
        }
        dfs(b, 0, dstB);
        ans = max(ans, dstA[b]);

        int cur_dst = INF;
        for(auto it : nodes) {
            if(cur_dst >= max(dstA[it], dstB[it])) {
                cur_dst = max(dstA[it], dstB[it]);
            }
        }
        dst.push_back(cur_dst);
    }
    sort(dst.rbegin(), dst.rend());
    if(dst.size() > 1) {
        ans = max(ans, dst[0] + dst[1] + l);
    }
    if(dst.size() > 2) {
        ans = max(ans, 2 * l + dst[1] + dst[2]);
    }
    return ans;
}

Compilation message (stderr)

dreaming.cpp:11:28: warning: 'on_way' defined but not used [-Wunused-variable]
 static bool vis[MAXN + 1], on_way[MAXN + 1];
                            ^~~~~~

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