Submission #918702

#	Time	Username	Problem	Language	Result	Execution time	Memory
918702		waldi	Power Plant (JOI20_power)	C++17	100 / 100	145 ms	35852 KiB

power

#include <bits/stdc++.h>
#define FOR(i,p,k) for(int i=(p);i<=(k);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) (int(x.size()))
#define all(x) (x).begin(),(x).end()
using namespace std;

int main(){
	int n;
	scanf("%d", &n);
	vector<vector<int>> g(n+1);
	REP(i, n-1){
		int a, b;
		scanf("%d%d", &a, &b);
		g[a].emplace_back(b);
		g[b].emplace_back(a);
	}
	vector<int> czy(n+1);
	scanf("\n");
	FOR(i, 1, n){
		char c;
		scanf("%c", &c);
		czy[i] = c=='1';
	}
	
	vector<int> oj(n+1);
	vector<int> dp = czy;
	function<void(int, int)> dfs = [&](int w, int o){
		int t = -czy[w];
		for(int i : g[w]) if(i != o) oj[i] = w, dfs(i, w), t += dp[i];
		dp[w] = max(dp[w], t);
	};
	dfs(1, 0);
	int wyn = dp[1];
	FOR(i, 2, n) wyn = max(wyn, dp[i]+czy[oj[i]]);
	printf("%d", wyn);
	return 0;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:10:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
power.cpp:14:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |   scanf("%d%d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~
power.cpp:19:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |  scanf("\n");
      |  ~~~~~^~~~~~
power.cpp:22:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |   scanf("%c", &c);
      |   ~~~~~^~~~~~~~~~

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