Submission #670958

#	Time	Username	Problem	Language	Result	Execution time	Memory
670958		1bin	Dreaming (IOI13_dreaming)	C++14	100 / 100	73 ms	15216 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;

#define all(v) v.begin(), v.end()
typedef long long ll;
const int NMAX = 1e5 + 5;
int N, M, L, A[NMAX], B[NMAX], T[NMAX];
int v[NMAX], ix, mxd, r, ans;
vector<pair<int, int>> adj[NMAX], rt;

void dfs(int x, int p, int d){
    v[x] = 1;
    if(d > mxd) mxd = d, ix = x;
    for(auto&[nx, t] : adj[x]){
        if(nx == p) continue;
        dfs(nx, x, d + t);
    }
    return;
}

int dfs2(int x, int p, int d){
    if(d == mxd){
        int mx = max(d, mxd - d);
        if(mx < r) r = mx, ix = x;
        return 1;
    }
    int ret = 0;
    for(auto&[nx, t] : adj[x]){
        if(nx == p) continue;
        ret |= dfs2(nx, x, d + t);
    }
    if(ret) {
        int mx = max(d, mxd - d);
        if(mx < r) r = mx, ix = x;
    }
    return ret;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    for(int i = 0; i < M; i++){
        adj[A[i]].emplace_back(B[i], T[i]);
        adj[B[i]].emplace_back(A[i], T[i]);
    }
    for(int i = 0; i < N; i++)
        if(!v[i]) {
            mxd = -1; dfs(i, -1, 0);
            mxd = -1; dfs(ix, -1, 0);
            
            r = mxd + 1;
            ans = max(ans, mxd);
            dfs2(ix, -1, 0);
            rt.emplace_back(r, ix);
        }
    sort(all(rt)); reverse(all(rt));
    if(rt.size() > 1) ans = max(ans, rt[0].first + rt[1].first + L);
    if(rt.size() > 2) ans = max(ans, rt[1].first + rt[2].first + 2 * L);
    return ans;
}
/*
int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    cin >> N >> M >> L;
    for(int i = 0; i < M; i++) cin >> A[i] >> B[i] >> T[i];
    cout << travelTime(N, M, L, A, B, T);
    return 0;
}*/

Compilation message (stderr)

dreaming.cpp: In function 'void dfs(int, int, int)':
dreaming.cpp:15:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   15 |     for(auto&[nx, t] : adj[x]){
      |              ^
dreaming.cpp: In function 'int dfs2(int, int, int)':
dreaming.cpp:29:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   29 |     for(auto&[nx, t] : adj[x]){
      |              ^

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