Submission #727110

#	Time	Username	Problem	Language	Result	Execution time	Memory
727110		hoainiem	Dreaming (IOI13_dreaming)	C++14	0 / 100	1065 ms	8140 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define nmax 100008
const int inf = 1e9 + 7;
using namespace std;
typedef pair<int, int> pii;
pii operator+(pii x, int y){
    return (x.fi <= y) ? make_pair(y, x.fi) : ((x.se < y) ? make_pair(x.fi, y) : x);
}
pii operator+(pii x, pii y){
    return (x + y.fi) + y.se;
}
vector<pii>vt, l[nmax];
bool kt[nmax], vis[nmax];
int n, d = 0, ans = inf, diameter = 0, dis[2][nmax];
stack<int>s;
int a[nmax];
pii pf[nmax], sf[nmax];
vector<int>his;
void bfs(int root, int id, int k){
    for (int tmp : his)
        dis[id][tmp] = -1;
    s.push(root);
    dis[id][root] = 0;
    while (!s.empty()){
        int u = s.top();
        s.pop();
        if (k)
            his.push_back(u);
        kt[u] = vis[u] = true;
        for (pii it : l[u])
            if (dis[id][it.fi] == -1){
                dis[id][it.fi] = dis[id][u] + it.se;
                s.push(it.fi);
            }
    }
}
int calc(int rt){
    for (int tmp : his)
        kt[tmp] = false;
    his.clear();
    bfs(rt, 0, 1);
    int u = 0, v = 0, res = inf;
    for (int i = 1; i < n; i++)
        if (dis[0][u] < dis[0][i])
            u = i;
    bfs(u, 1, 0);
    for (int i = 1; i < n; i++)
        if (dis[1][v] < dis[1][i])
            v = i;
    bfs(v, 0, 0);
    for (int i = 0; i < n; i++)
        if (kt[i])
            res = min(res, max(dis[0][i], dis[1][i]));
    diameter = max(diameter, dis[0][u]);
    return res;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    memset(dis, -1, sizeof(dis));
    n = N;
    for (int i = 0; i < M; i++){
        int u = A[i], v = B[i], w = T[i];
        l[u].push_back({v, w});
        l[v].push_back({u, w});
    }
//    assert(M == N - 2);
    fill(vis, vis + n + 1, false);
    pf[0] = {-inf, -inf};
    for (int i = 0; i < N; i++)
        if (!vis[i]){
            a[++d] = calc(i);
            pf[d] = pf[d - 1] + a[d];
        }
    if (M == N - 2)
        return max(diameter, a[2] + a[1] + L);
    return 0;
    sf[d + 1] = {-inf, -inf};
    for (int i = d; i > 0; i--)
        sf[i] = sf[i + 1] + a[i];
    for (int i = 1; i <= d; i++){
        pii cur = pf[i - 1] + sf[i + 1];
        ans = min(ans, max({diameter, cur.fi + cur.se + L * 2, cur.fi + a[i] + L}));
    }
    return ans;
}

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