Submission #960732

#	Time	Username	Problem	Language	Result	Execution time	Memory
960732		GrindMachine	007 (CEOI14_007)	C++17	100 / 100	217 ms	36040 KiB

007

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

read the edi some time ago, remember some ideas from there

*/

const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<int> adj1[N], adj2[N];
vector<bool> vis(N);
vector<int> topo;

void dfs1(int u){
    vis[u] = 1;
    trav(v,adj2[u]){
        if(vis[v]) conts;
        dfs1(v);
    }

    topo.pb(u);
}

void solve(int test_case)
{
    int n,m; cin >> n >> m;
    int s,d,x,y; cin >> s >> d >> x >> y;
    rep1(i,m){
        int u,v; cin >> u >> v;
        adj1[u].pb(v), adj1[v].pb(u);
    }

    auto bfs = [&](int src){
        queue<int> q;
        vector<int> dis(n+5,inf1);
        q.push(src);
        dis[src] = 0;

        while(!q.empty()){
            int u = q.front();
            q.pop();

            trav(v,adj1[u]){
                if(dis[v] != inf1) conts;
                q.push(v);
                dis[v] = dis[u]+1;
            }
        }

        return dis;
    };

    auto disd = bfs(d);
    auto disx = bfs(x);
    auto disy = bfs(y);

    rep1(u,n){
        trav(v,adj1[u]){
            if(disx[v] == disx[u]-1 and disy[v] == disy[u]-1){
                adj2[u].pb(v);
            }
        }
    }

    rep1(i,n){
        if(vis[i]) conts;
        dfs1(i);
    }

    vector<int> dp(n+5);
    trav(u,topo){
        trav(v,adj2[u]){
            amax(dp[u],dp[v]+1);
        }
    }

    vector<bool> win(n+5); // does 007 win if dr.null starts at u (no turns skipped)?
    rep1(u,n){
        int x1 = disx[s], y1 = disy[s];
        int x2 = disx[u], y2 = disy[u];
        bool curr_win;

        if(x2 < x1 or y2 < y1){
            curr_win = false;
        }
        else{
            if(x1 < x2 or y1 < y2){
                curr_win = true;
            }
            else{
                if(dp[u] > dp[s]){
                    curr_win = false;
                }
                else{
                    curr_win = true;
                }
            }
        }

        win[u] = curr_win;
    }

    vector<bool> dis_win(n+5,1);
    rep1(u,n){
        if(!win[u]){
            // cant wait for time = dis(u,d)
            dis_win[disd[u]] = 0;
        }
    }

    int ans = -1;
    rep(i,n+1){
        if(!dis_win[i]) break;
        ans = i;
    }

    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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