Submission #1084347

#	Time	Username	Problem	Language	Result	Execution time	Memory
1084347		Boycl07	Power Plant (JOI20_power)	C++17	100 / 100	81 ms	29584 KiB

power

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

typedef long long ll;
typedef unsigned long long ull;

#define rep(i, n) for(int i = 1; (i) <= (n); ++i)
#define forn(i, l, r) for(int i = (l); i <= (r); ++i)
#define ford(i, r, l) for(int i = (r); i >= (l); --i)
#define FOR(i, n) for(int i = 0; i < (n); ++i)
#define FORD(i, n) for(int i = ((n) - 1); i >= 0; --i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define endl "\n"
#define task "BAI1"
#define sz(a) int(a.size())
#define C(x, y) make_pair(x, y)
#define all(a) (a).begin(), (a).end()
#define bit(i, mask) (mask >> i & 1)

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }

inline int readInt()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();int n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline ll readLong()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();ll  n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline string readString() {char c;while(c=getchar(),c==' '||c=='\n'||c=='\t');string s({c});while(c=getchar(),c!=EOF&&c!=' '&&c!='\n'&&c!='\t')s+=c;return s;}

const int N = 2e5 + 3;
const int M = 1e3 + 3;
const int LOG = 50;
const int MOD = 1e9 + 7;
const ll INF = 1e18;


int n;

vector<int> g[N];

string s;

int dp[N][2];

int res = 0;

void dfs(int u, int p)
{
    for(int v : g[u]) if(v != p)
    {
        dfs(v, u);
        maximize(dp[u][0], max(dp[v][0], dp[v][1]));
    }

    dp[u][1] = s[u - 1] - '0';
    int cur = -(s[u - 1] - '0');

    for(int v : g[u]) if(v != p)
        cur += max(0, dp[v][1]);
    int Max = 0;
    for(int v : g[u]) if(v != p) maximize(Max, dp[v][1]);




    maximize(dp[u][1], cur);

    maximize(res, dp[u][1]);
    maximize(res, Max + (s[u - 1] - '0'));
}

void solve()
{
    cin >> n;
    rep(i, n - 1)
    {
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    cin >> s;
    dfs(1, 1);
    cout << res;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int TC = 1;

    if(fopen("note.inp", "r"))
    {
        freopen("note.inp", "r", stdin);
        freopen("note.out", "w", stdout);
    }

    while(TC--)
    {
        solve();
        cout << endl;
    }

    return 0;
}

Compilation message (stderr)

power.cpp: In function 'int main()':
power.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen("note.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen("note.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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