Submission #615828

#	Time	Username	Problem	Language	Result	Execution time	Memory
615828		HediChehaidar	Virus Experiment (JOI19_virus)	C++17	0 / 100	200 ms	121320 KiB

virus

#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define dte  tuple<double , double , double>
using namespace std;
const int INF = 1000*1000*1000; // 1 e 9
const int MOD = 1e9 + 7;//998244353 ;
const double EPS = 0.000000001; // 1 e -9
const ll inf = (ll)1e18;

pii d[4] = { {1 , 0} , {0 , 1} , {-1 , 0} , {0 , -1} };
string dir = "NWSE";
map<char , int> mp;
int n , m , q;
vi adj[(int)7e5 + 10];
vi rev[(int)7e5 + 10];
vi g[(int)7e5 + 10];
bool vis[(int)7e5 + 10];
bool ok[(int)7e5 + 10];
int idx[(int)7e5 + 10];
stack<int> st;
vector<vi> scc;
string s;
int cur = 0;
vi v;
void dfs2(int pos){
    if(vis[pos]) return ;
    vis[pos] = true;
    idx[pos] = cur;
    v.pb(pos);
    for(auto c : rev[pos]) dfs2(c);
}
void dfs(int pos){
    if(vis[pos]) return;
    vis[pos] = true;
    for(auto c : adj[pos]) dfs(c);
    st.push(pos);
}
int grid[808][808];
int nb[4];
int main(){
    //ifstream fin ("testing.txt");
    //ofstream fout ("output.txt");
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    for(int i = 0 ; i < 4 ; i++) mp[dir[i]] = i;
    cin>>q>>n>>m;
    cin>>s;
    for(int i = 0 ; i < q ; i++){
        int id = mp[s[i]];
        for(int j = i + 1 ; j <= q ; j++){
            if( j == q || s[j] != s[j-  1] ) {
                nb[id] = max(nb[id] , j - i);
                i = j - 1; break;
            }
        }
    }
    if(s[0] == s.back()){
        int cnt = 1;
        for(int i = 0 ; i < q - 1 ; i++){
            if(s[i] != s[0]) break;
            cnt++;
        }
        nb[mp[s[0]]] = max(nb[mp[s[0]]] , cnt);
    }
    //for(int i = 0 ; i < 4 ; i++) cout << nb[i] << endl;
    for(int i = 0 ; i < n ; i++){
        for(int j = 0 ; j < m ; j++) cin>>grid[i][j];
    }
    for(int i = 0 ; i < n ; i++){
        for(int j = 0 ; j < m ; j++){
            if(grid[i][j] == 0) continue;
            int a = i * m + j;
            ok[a] = true;
            for(int k = 0 ; k < 4 ; k++){
                int x = i + d[k].ff , y = j + d[k].ss;
                if(x < 0 || y < 0 || x == n || y == m) continue;
                if(grid[x][y] == 0) continue;
                int b = x * m + y;
                //if(a == 2 && b == 3) cout << k << " " << grid[x][y] << "\n";
                if(nb[k] >= grid[x][y]){
                    adj[a].pb(b); rev[b].pb(a);
                }
            }
        }
    }
    n = (n - 1) * m + m;
    /*for(int i = 0 ; i < n ; i++){
        cout << i << "   ";
        for(auto c : adj[i]) cout << c << " "; cout << "\n";
    }*/
    for(int i = 0 ; i < n ; i++) if(!vis[i] && ok[i]) dfs(i);
    memset(vis , 0 , sizeof vis);
    while(!st.empty()){
        int a = st.top(); st.pop();
        if(vis[a]) continue;
        dfs2(a);
        scc.pb(v);
        v.clear();
        cur++;
    }
    /*cout << cur << "\n";
    for(auto c : scc){
        for(auto e : c) cout << e << " "; cout << "\n";
    }*/
    //memset(vis , 0 , sizeof vis);
    for(int i = 0 ; i < n ; i++){
        if(!ok[i]) continue;
        for(auto c : adj[i]) if(idx[i] != idx[c]) g[idx[i]].pb(idx[c]);
    }
    int res = INF , cnt = 0;
    for(int i = 0 ; i < cur ; i++){
        if(g[i].empty() && scc[i].size() <= res){
            //cout << scc[i][0] << "\n";
            if(scc[i].size() < res ) cnt = 0;
            cnt++;
            res = min(res , (int)scc[i].size());
        }
    }
    cout << res <<  " " << cnt << "\n";
    return 0;
}

/*
    Think of : BS / DFS / BFS / SSSP / SCC / MSP / MAX FLOW / TOPSORT / LCA / MATRIX / DP(bitmask) / 2 POINTERS / SEG TREE / MATH / UN FIND / MO / HLD
    Read the statement CAREFULLY !!
    Make a GREADY APPROACH !!!! (start from highest / lowest)
    Make your own TESTS !!
    Be careful from CORNER CASES !
*/

Compilation message (stderr)

virus.cpp: In function 'int main()':
virus.cpp:128:42: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  128 |         if(g[i].empty() && scc[i].size() <= res){
      |                            ~~~~~~~~~~~~~~^~~~~~
virus.cpp:130:30: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  130 |             if(scc[i].size() < res ) cnt = 0;
      |                ~~~~~~~~~~~~~~^~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 6
• Subtask 3: 0 / 80