Submission #1020211

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020211		cpptowin	Power Plant (JOI20_power)	C++17	100 / 100	125 ms	49748 KiB

power

#include<bits/stdc++.h>
#define fo(i,l,r) for(int i = l ; i <= r ; i ++)
#define fod(i,r,l) for(int i = r ; i >= l ; i--)
#define pb emplace_back
#define int long long
#define maxn 1000010
#define N 1010
#define inf (int)1e18
#define bitcount(x) __builtint_popcount(x)
#define bit(x,i) ((x >> i) & 1)
#define onbit(x,i) (x | (1ll << i))
#define offbit(x,i) (x ^ (1ll << i))
#define lb(x) x & -x
#define all(x) x.begin(),x.end()
#define ss(x) (int)x.size()
#define en cout << "\n";
#define vi vector<int>
#define pii pair<int,int>
#define vii vector<pii>
using namespace std;
bool maximize(int &a,int b)
{
    if(a <= b)
    {
        a = b;
        return 1;
    }
    return 0;
}
bool minimize(int &a,int b)
{
    if(a >= b)
    {
        a = b;
        return 1;
    }
    return 0;
}
int n,a[maxn],f[maxn];
vi ke[maxn];
int ans = 0;
void dfs(int u,int par = 0)
{
    int sum = 0,maxx = 0;
    for(int v : ke[u]) if(v != par)
    {
        dfs(v,u);
        maximize(maxx,f[v]);
        sum += f[v];
    }
    if(a[u])
    {
        maximize(ans,maxx + 1);
        maximize(ans,sum - 1);
    }
    else maximize(ans,sum);
    f[u] = max(a[u],sum - a[u]);
}
main()
{
#define name "TASK"
    if(fopen(name".inp","r"))
    {
        freopen(name".inp","r",stdin);
        freopen(name".out","w",stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    fo(i,1,n - 1)
    {
        int u,v;
        cin >> u >> v;
        ke[u].pb(v);
        ke[v].pb(u);
    }
    fo(i,1,n)
    {
        char t;
        cin >> t;
        a[i] = t - '0';
    }
    dfs(1);
    cout << ans;
}

Compilation message (stderr)

power.cpp:59:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   59 | main()
      | ^~~~
power.cpp: In function 'int main()':
power.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(name".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
power.cpp:65:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         freopen(name".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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