Submission #311801

#	Time	Username	Problem	Language	Result	Execution time	Memory
311801		MarcoMeijer	Power Plant (JOI20_power)	C++14	100 / 100	309 ms	45752 KiB

power

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

// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }

// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }

//===================//
//  Added libraries  //
//===================//

//===================//
//end added libraries//
//===================//

void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}


//===================//
//   begin program   //
//===================//

const int MX = 5e5;

int n, m=0;
int a[MX], b[MX];
int rev[MX];
vi adj[MX];
int p[MX];
string s;

int dp[MX];
int sm[MX], skip[MX];
int getAns(int e);
int getSum(int e) {
    int p=a[e], u=b[e];
    if(sm[u] == -1) {
        sm[u] = 0;
        FOR(v,adj[u]) if(b[v] != p) sm[u] += getAns(v);
        skip[u] = p;
    } else if(skip[u] != -1 && skip[u] != p) {
        FOR(v,adj[u]) if(b[v] == skip[u]) sm[u] += getAns(v);
        skip[u] = -1;
    }
    int res = sm[u];
    if(skip[u] != p) res -= getAns(rev[e]);
    return res;
}
int getAns(int e) {
    if(dp[e] != -1) return dp[e];

    int p=a[e], u=b[e];

    dp[e] = 0;
    if(s[u]) {
        dp[e] = getSum(e)-1;
        dp[e] = max(dp[e], 1);
    } else {
        dp[e] = getSum(e);
    }

    return dp[e];
}

void program() {
    IN(n);
    RE(i,n-1) {
        int u, v;
        IN(u,v); u--; v--;
        a[m] = u; b[m] = v; rev[m] = m+1;
        adj[u].pb(m++);
        a[m] = v; b[m] = u; rev[m] = m-1;
        adj[v].pb(m++);
    }
    IN(s); RE(i,n) s[i]-='0';
    RE(i,m) dp[i] = sm[i] = -1;

    int ans = 0;
    RE(u,n) {
        if(!s[u]) continue;
        ans = max(ans, 1);
        FOR(v,adj[u]) ans = max(ans, 1+getAns(v));
    }
    OUTL(ans);
}

Compilation message (stderr)

power.cpp: In function 'int getAns(int)':
power.cpp:94:9: warning: unused variable 'p' [-Wunused-variable]
   94 |     int p=a[e], u=b[e];
      |         ^

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 53 / 53