Submission #345551

#	Time	Username	Problem	Language	Result	Execution time	Memory
345551		79brue	Dreaming (IOI13_dreaming)	C++14	32 / 100	62 ms	13420 KiB

dreaming

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

using namespace std;

typedef long long ll;

int n, m, k;
vector<pair<int, int> > link[100002];
int DP[100002], DP2[100002];
bool visited[100002];
int ans;

int minVal;
vector<int> vec;

void dfs(int x){
    visited[x] = 1;
    for(auto y: link[x]){
        if(visited[y.first]) continue;
        dfs(y.first);

        int tmp1 = DP[y.first] + y.second;
        int tmp2 = DP2[y.first] + y.second;
        if(DP2[x] < tmp1) DP2[x] = tmp1;
        if(DP2[x] > DP[x]) swap(DP[x], DP2[x]);
        if(DP2[x] < tmp2) DP2[x] = tmp2;
    }
    if(DP[x] < 0) DP[x] = 0;
    ans = max(ans, DP[x] + DP2[x]);
    visited[x] = 0;
}
void dfs2(int x, int fromUp){
    visited[x] = 1;
    minVal = min(minVal, max(fromUp, DP[x]));
    for(auto y: link[x]){
        if(visited[y.first]) continue;
        dfs2(y.first, max(fromUp, (DP[x] == DP[y.first] + y.second) ? DP2[x] : DP[x]) + y.second);
    }
}

int travelTime(int _n, int _m, int _k, int x[], int y[], int z[]){
    n = _n, m = _m, k = _k;
    for(int i=0; i<n; i++) DP[i] = DP2[i] = -1e9;
    for(int i=0; i<m; i++){
        link[x[i]].push_back(make_pair(y[i], z[i]));
        link[y[i]].push_back(make_pair(x[i], z[i]));
    }

    for(int i=0; i<n; i++){
        if(!visited[i]){
            minVal = INT_MAX;
            dfs(i);
            dfs2(i, 0);
            vec.push_back(minVal);
        }
    }
    sort(vec.rbegin(), vec.rend());
    if(vec.size() >= 2) ans = max(ans, vec[0] + k + vec[1]);
    if(vec.size() >= 3) ans = max(ans, vec[1] + k + k + vec[2]);
    return ans;
}

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