Submission #1299174

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299174		khoile08	Power Plant (JOI20_power)	C++20	100 / 100	153 ms	25940 KiB

power

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

#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FOD(i, a, b) for(int i = a; i >= b; i--)
//#define int long long
#define fi first
#define se second
#define ll long long
#define db double 
#define pb push_back
#define ii pair<int,int>
#define sq(i) (1LL * (i) * (i))
#define MASK(i) (1LL << i)
#define task "task"

const int inf = 1e9;
const ll INF = 1e18;
const int N = 2e5 + 4;

int n, res;
vector<int> g[N];
bool ch[N];
int dp[N];

void dfs(int u, int p) {
    for(int v : g[u]) {
        if(v == p) continue;
        dfs(v, u);
        dp[u] += dp[v];
        res = max(res, dp[v] + ch[u]);
    }
    dp[u] -= ch[u];
    dp[u] = max(dp[u], (int)ch[u]);
}

signed main() {
    if(fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout); 
    }
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n;
    FOR(i, 1, n - 1) {
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    FOR(i, 1, n) {
        char c; 
        cin >> c;
        ch[i] = (c == '1');
    }

    dfs(1, -1);
    FOR(i, 1, n) res = max(res, dp[i]);
    cout << res << '\n';
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:39:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:40:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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