Submission #293186

#	Time	Username	Problem	Language	Result	Execution time	Memory
293186		CaroLinda	Power Plant (JOI20_power)	C++14	100 / 100	216 ms	27148 KiB

power

#include <bits/stdc++.h>

#define pb push_back
#define ll long long
#define pii pair<int,int>
#define mk make_pair
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
#define debug printf
#define lp(i,a,b) for(int i = a ; i < b ; i++ )
#define sz(x) (int)(x.size())

const int MAXN = 2e5+10 ;

using namespace std ;

int N ;
int dp[MAXN][2] ;
vector<int> adj[MAXN] ;
bool isPower[MAXN] ;
char str[MAXN] ;

void dfs(int x, int dad)
{

    int mx[2] = {0,0} ;
    int soma1 = 0 ;

    for(auto e : adj[x] )
    {
        if(e == dad) continue ;

        dfs(e,x) ;

        lp(i,0,2) mx[i] = max(mx[i] , dp[e][i]) ;
        soma1 += dp[e][1] ;
    }

    if(!isPower[x])
    {
        dp[x][0] = max( soma1, mx[0] ) ;
        dp[x][1] = soma1 ;
    }
    else
    {
        dp[x][0] = max( mx[1] + 1 , soma1 - 1 ) ;
        dp[x][0] = max( dp[x][0] , mx[0] ) ;

        dp[x][1] = max( 1 , soma1 - 1 ) ;
    }

}

int main()
{
    scanf("%d", &N) ;
    for(int i = 1 , u ,v ; i < N ; i++ )
    {
        scanf("%d%d", &u, &v ) ;

        adj[u].pb(v) ;
        adj[v].pb(u) ;
    }

    scanf("%s", str ) ;
    lp(i,0,N) isPower[i+1] = ( str[i] == '1' ) ;

    dfs(1,-1) ;
    printf("%d\n" , dp[1][0]) ;

}

/*
6
2 1
2 3
2 4
2 5
2 6
111111

6
2 1
2 3
2 4
2 5
2 6
011111

5
1 2
2 3
3 4
4 5
11100

6
2 1
2 3
2 4
2 5
2 6
010101

16
14 10
14 13
14 16
13 11
11 12
13 15
13 5
16 3
16 8
16 1
12 4
4 7
10 2
7 6
16 9
1111111111111111

10
1 4
2 4
3 4
4 5
5 7
7 6
7 8
7 9
7 10
1111111111
*/

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:57:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |     scanf("%d", &N) ;
      |     ~~~~~^~~~~~~~~~
power.cpp:60:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   60 |         scanf("%d%d", &u, &v ) ;
      |         ~~~~~^~~~~~~~~~~~~~~~~
power.cpp:66:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   66 |     scanf("%s", str ) ;
      |     ~~~~~^~~~~~~~~~~~

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