Submission #1095620

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095620		TrinhKhanhDung	Dreaming (IOI13_dreaming)	C++14	100 / 100	46 ms	17784 KiB

dreaming

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18 + 10
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)
#include "dreaming.h"

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 1e5 + 10;

int n, m, l;
vector<pair<int, int>> adj[MAX];
int dp_in[MAX], dp_out[MAX];
bool visited[MAX];

void dfs1(vector<int> &save, int u, int p = -1){
    visited[u] = true;
    save.push_back(u);
    for(auto o: adj[u]){
        int v = o.fi, c = o.se;
        if(v == p) continue;
        dfs1(save, v, u);
        maximize(dp_in[u], dp_in[v] + c);
    }
}

void dfs2(int u, int p = -1){
    int first = dp_out[u], second = 0;
    for(auto o: adj[u]){
        int v = o.fi, c = o.se;
        if(v == p) continue;
        if(dp_in[v] + c > first){
            second = first;
            first = dp_in[v] + c;
        }
        else maximize(second, dp_in[v] + c);
    }
    for(auto o: adj[u]){
        int v = o.fi, c = o.se;
        if(v == p) continue;
        if(dp_in[v] + c == first)
            dp_out[v] = second + c;
        else
            dp_out[v] = first + c;
        dfs2(v, u);
    }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    n = N;
    m = M;
    l = L;
    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]});
    }

    vector<int> ord;

    for(int i = 0; i < n; i++) if(!visited[i]){
        vector<int> save;
        dfs1(save, i);
        dfs2(i);
        int mi = INF * 2;
        for(int x: save) minimize(mi, max(dp_in[x], dp_out[x]));
        ord.push_back(mi);
    }

    sort(ALL(ord), greater<int>());
    int ans = 0;
    if(m + 1 == n) ans = ord[0];
    else{
        maximize(ans, ord[0] + ord[1] + l);
        if(sz(ord) > 2) maximize(ans, ord[1] + ord[2] + 2 * l);
    }

    for(int i = 0; i < n; i++) maximize(ans, dp_in[i] + dp_out[i]);

    return ans;
}

//void solve(){
//
//}
//
//int main(){
//    ios_base::sync_with_stdio(0); cin.tie(0);
////     freopen("bdbang.inp","r",stdin);
////     freopen("bdbang.out","w",stdout);
//
//    cout << travelTime(12, 8, 2, {0,8,2,5,5,1,1,10}, {8,2,7,11,1,3,9,6}, {4,2,4,3,7,1,5,3});
//
//    return 0;
//}

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