Submission #65060

#	Time	Username	Problem	Language	Result	Execution time	Memory
65060		bazsi700	007 (CEOI14_007)	C++14	100 / 100	550 ms	17660 KiB

007

#include <bits/stdc++.h>

using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n,m,s,d,a,b;
    cin >> n >> m >> s >> d >> a >> b;
    vector<vector<int> > graph(n+1,vector<int>());
    for(int i = 0; i < m; i++) {
        int x,y;
        cin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    vector<bool> wass(n+1,false);
    vector<int> dists(n+1,0);
    vector<bool> wasd(n+1,false);
    vector<int> distd(n+1,0);
    vector<bool> wasa(n+1,false);
    vector<int> dista(n+1,0);
    vector<bool> wasb(n+1,false);
    vector<int> distb(n+1,0);
    wass[s] = true;
    queue<int> q;
    q.push(s);
    while(!q.empty()) {
        int v = q.front();
        q.pop();
        for(int u : graph[v]) {
            if(!wass[u]) {
                wass[u] = true;
                q.push(u);
                dists[u] = dists[v]+1;
            }
        }
    }
    wasd[d] = true;
    q.push(d);
    while(!q.empty()) {
        int v = q.front();
        q.pop();
        for(int u : graph[v]) {
            if(!wasd[u]) {
                wasd[u] = true;
                q.push(u);
                distd[u] = distd[v]+1;
            }
        }
    }
    wasa[a] = true;
    q.push(a);
    while(!q.empty()) {
        int v = q.front();
        q.pop();
        for(int u : graph[v]) {
            if(!wasa[u]) {
                wasa[u] = true;
                q.push(u);
                dista[u] = dista[v]+1;
            }
        }
    }
    wasb[b] = true;
    q.push(b);
    while(!q.empty()) {
        int v = q.front();
        q.pop();
        for(int u : graph[v]) {
            if(!wasb[u]) {
                wasb[u] = true;
                q.push(u);
                distb[u] = distb[v]+1;
            }
        }
    }
    if(dists[a] == dists[b] && distd[a] == distd[b]) {
        int mxdistda = n;
        int mxdistdb = n;
        int mxdistsa = n;
        int mxdistsb = n;
        for(int i = 1; i <= n; i++) {
            if(dista[i] == distb[i]) {
                if(dista[i]+distd[i] == distd[a]) {
                    mxdistda = min(mxdistda,dista[i]);
                }
                if(distb[i]+distd[i] == distd[b]) {
                    mxdistdb = min(mxdistdb,distb[i]);
                }
                if(dista[i]+dists[i] == dists[a]) {
                    mxdistsa = min(mxdistsa,dista[i]);
                }
                if(distb[i]+dists[i] == dists[b]) {
                    mxdistsb = min(mxdistsb,distb[i]);
                }
            }
        }
        if(mxdistsa > mxdistda && mxdistsb > mxdistdb) {
            cout << max(min(distd[a]-dists[a],distd[b]-dists[b])-1,-1);
        } else {
            cout << max(min(distd[a]-dists[a],distd[b]-dists[b]),-1);
        }
    } else {
        cout << max(min(distd[a]-dists[a],distd[b]-dists[b]),-1);
    }
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70