Submission #295458

#	Time	Username	Problem	Language	Result	Execution time	Memory
295458		dsabolic	Power Plant (JOI20_power)	C++17	Compilation error	0 ms	0 KiB

power

#include <bits/stdc++.h>

#define rep(i, a, n) for(int (i) = (a); (i) < (n); ++(i))

using namespace std;

const int N = 2e5 + 50;

int n;
vector<int> graph[N];
string s;
int dp[N];
int sol = 0;

int rek(int v, int p) {
        int sum = 0, mx = 0, cnt = 0;
        for(auto n : graph[v]) {
                if(n == p) continue;
                int val = rek(n, v);
                if(val) cnt++;
                sum += val;
                mx = max(mx, val);
        }


        //if(s[v] == '0' || cnt > 1) dp[v] = max(s[v] - '0', sum - s[v] + '0');
        dp[v] = max(s[v] - '0', sum - (s[v] - '0'));
        else dp[v] = max(1, sum);

        if(s[v] == '1') {
                sol = max(sol, max(mx + 1, dp[v]));
        } else {
                sol = max(sol, dp[v]);
        }

        return dp[v];
}

int main() {
        cin >> n;
        rep(i, 0, n - 1) {
                int a, b;
                cin >> a >> b;
                --a, --b;
                graph[a].push_back(b);
                graph[b].push_back(a);
        }
        cin >> s;

        rek(0, -1);
        printf("%d\n", sol);

        return 0;
}

Compilation message (stderr)

power.cpp: In function 'int rek(int, int)':
power.cpp:28:9: error: 'else' without a previous 'if'
   28 |         else dp[v] = max(1, sum);
      |         ^~~~
power.cpp: In function 'int main()':
power.cpp:3:30: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
    3 | #define rep(i, a, n) for(int (i) = (a); (i) < (n); ++(i))
      |                              ^
power.cpp:41:9: note: in expansion of macro 'rep'
   41 |         rep(i, 0, n - 1) {
      |         ^~~