Submission #335853

#	Time	Username	Problem	Language	Result	Execution time	Memory
335853		saarang123	Dreaming (IOI13_dreaming)	C++14	47 / 100	153 ms	18284 KiB

dreaming

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

vector<vector<array<int, 2>>> g;
vector<array<int, 2>> cost;
vector<bool> vis;
vector<array<int, 2>> par;

array<int, 2> dfs(int v, int p, int d) {
    vis[v] = true;
    par[v] = {p, d};
    array<int, 2> ret = {d, v};
    for(auto tx : g[v]) {
        int u = tx[0], w = tx[1];
        if(u == p) continue;
        ret = max(ret, dfs(u, v, d + w));
    }
    return ret;
}

int travelTime(int N,int M,int L, int A[],int B[],int T[]) {
    g.resize(N);
    vis.resize(N);
    par.resize(N);
    for(int i = 0; i < M; i++) {
        g[A[i]].push_back({B[i], T[i]});
        g[B[i]].push_back({A[i], T[i]});
    }
    for(int i = 0; i < N; i++) {
        if(vis[i]) continue;
        array<int, 2> x = dfs(i, -1, 0);
        array<int, 2> d = dfs(x[1], -1, 0);
        vector<array<int, 2>> diam;
        array<int, 2> v = {d[1], d[0]};
        while(v[0] != -1) {
            diam.push_back({v[0], par[v[0]][1]});
            v = par[v[0]];
        }
        array<int, 4> ans = {d[0], d[0], 0, d[1]};
        for(auto x : diam) ans = min(ans, {abs(d[0] - 2 * x[1]), d[0] - x[1], x[1], x[0]});
        //cout << ans[1] << ' ' << ans[2] << ' ' << ans[3] << '\n';
        cost.push_back({d[0], ans[3]});
    }
    sort(cost.rbegin(), cost.rend());
    for(int i = 1; i < cost.size(); i++) {
        g[cost[0][1]].push_back({cost[i][1], L});
        g[cost[i][1]].push_back({cost[0][1], L});
    }
    array<int, 2> x = dfs(1, -1, 0);
    int answer = dfs(x[1], -1, 0)[0];
    return answer;
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:46:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |     for(int i = 1; i < cost.size(); i++) {
      |                    ~~^~~~~~~~~~~~~

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