Submission #955633

#	Time	Username	Problem	Language	Result	Execution time	Memory
955633		vjudge1	Power Plant (JOI20_power)	C++17	100 / 100	154 ms	31568 KiB

power

#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long
#define all(x) x.begin(), x.end()
#define Neco "Power Plant"
#define resp(x) sort(all(x)), x.resize(unique(all(x)) - x.begin())
#define getbit(x,i) ((x >> i)&1)
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define cntbit(x) __builtin_popcountll(x)
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define maxn (int) 2e5 + 7

using namespace std;

const ll mod = 1e9 + 7; //972663749
const ll base = 911382323;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

ll GetRandom(ll l, ll r)
{
    return uniform_int_distribution<ll> (l, r)(rng);
}

int n;
int cl[maxn];
vector<int> edges[maxn];

namespace Sub1
{
    int a[maxn];

    int calc(int u, int par) {
        int ans = 0;
        for(int v : edges[u]) if(v != par) ans += calc(v, u) > 0;
        if(a[u]) ans = max(ans, 1);
        return ans;
    }

    int solve()
    {
        int ans = 1;
        fi(x, 1, (1 << n) - 1)
        {
            fi(i, 1, n) {
                a[i] = 0;
                if(getbit(x, i - 1)) a[i] = cl[i];
            }

            int sum = 0;
            fi(i, 1, n) if(cl[i])
            {
                int w = calc(i, 0);
                if(w > 1) sum --;
                else sum += (w == 1) && a[i];
            }
            ans = max(ans, sum);
        }
        return ans;
    }

}

namespace Sub2
{
    int res = 1;
    int dp[maxn];

    void dfs(int u, int par)
    {
        vector<int> P;
        for(int v : edges[u]) if(v != par) {
            dfs(v, u);
            P.push_back(dp[v]);
        }

        sort(all(P), greater<int>());

        int ans = cl[u];
        int sum = 0;

        if(P.size() >= 1)
        {
            res = max(res, P[0] + cl[u]), ans = max(ans, P[0] + cl[u]);

            fi(i, 0, P.size() - 1) {
                sum += P[i];
                if(i > 0) res = max(res, sum - cl[u]), ans = max(ans, sum - cl[u]);
            }
            dp[u] = sum;
        }

        if(cl[u]) dp[u] = max(dp[u] - 1, 1);
    }

    int solve()
    {
        res = 1;
        fi(i, 1, n) dp[i] = 0;
        dfs(1, 0);
        return res;
    }

}


void Input()
{
    cin >> n;

    fi(i, 1, n - 1) {
        int x, y;
        cin >> x >> y;
        edges[x].push_back(y), edges[y].push_back(x);
    }

    fi(i, 1, n) {
        char x; cin >> x;
        cl[i] = x - '0';
    }
}

pair<int, int> E[maxn];
void gen()
{
    n = GetRandom(2, 16);

    fi(i, 1, n) edges[i].clear();

    fi(i, 1, n - 1) {
        int x = i + 1, y = GetRandom(1, i);
        edges[x].push_back(y), edges[y].push_back(x);
        E[i] = {x, y};
    }

    fi(i, 1, n) cl[i] = GetRandom(0, 1);
}

void Print()
{
    cout << n << '\n';
    fi(i, 1, n - 1) {
        cout << E[i].first << " " << E[i].second << '\n';
    }
    fi(i, 1, n) cout << cl[i];
    cout << '\n';
    cout << "-----------------------\n";
}


void solve()
{

    Input();

    cout << Sub2::solve();

}


int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

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


    int nTest = 1;
//    cin >> nTest;


    while(nTest--)
    {
        solve();
    }


    return 0;
}

Compilation message (stderr)

power.cpp: In function 'int Sub1::solve()':
power.cpp:50:32: warning: suggest parentheses around '-' inside '>>' [-Wparentheses]
   50 |                 if(getbit(x, i - 1)) a[i] = cl[i];
      |                              ~~^~~
power.cpp:8:28: note: in definition of macro 'getbit'
    8 | #define getbit(x,i) ((x >> i)&1)
      |                            ^
power.cpp: In function 'void Sub2::dfs(int, int)':
power.cpp:12:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 | #define fi(i, a, b) for(int i = a; i <= b; i++)
......
   89 |             fi(i, 0, P.size() - 1) {
      |                ~~~~~~~~~~~~~~~~~~     
power.cpp:89:13: note: in expansion of macro 'fi'
   89 |             fi(i, 0, P.size() - 1) {
      |             ^~
power.cpp: In function 'int main()':
power.cpp:172:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  172 |         freopen(Neco".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:173:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  173 |         freopen(Neco".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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