Submission #91824

#	Time	Username	Problem	Language	Result	Execution time	Memory
91824		karma	Triumphal arch (POI13_luk)	C++11	100 / 100	1375 ms	22776 KiB

luk

#include<bits/stdc++.h>
#define For(i, a, b)  for(int i = a, _b = b; i <= _b; ++i)
#define Ford(i, a, b) for(int i = a, _b = b; i >= _b; --i)
#define FileName      "test"
#define ll            long long
#define ld            long double
#define ull           unsigned long
#define Print(x)      cerr << #x << "is " << x << '\n';
#define pb            push_back
#define X             first
#define Y             second
//#define Karma

using namespace std;

template<typename T> inline void Cin(T &x)
{
    char c;
    T sign = 1;
    x = 0;
    for (c = getchar(); c < '0' || c > '9'; c = getchar())
        if (c == '-') sign = -1;
    for (; c >= '0' && c <= '9'; c = getchar())
        x = x * 10 + c - '0';
    x *= sign;
}
template <typename T> inline void Out(T x) {if(x > 9) Out(x / 10); putchar(x % 10 + '0');}
template <typename T> inline void Cout(T x, char c) {if(x < 0) putchar('-'); x = abs(x); Out(x); putchar(c);}
template <typename T, typename... Args> inline void Cin(T& a, Args&... args) {Cin(a);Cin(args...);}
template <typename T, typename... Args> inline void Cout(T a, char c, Args... args) {Cout(a, c);Cout(args...);}

typedef pair<int, int> pii;
typedef pair<ll, int> plli;
const int N = 3e5 + 7;

int n, crew, u, v;
vector<int> a[N];

void DFS(int u, int par)
{
    For(i, 0, a[u].size() - 1)
        if(a[u][i] == par) swap(a[u][i], a[u][a[u].size() - 1]);
    if(u > 1) a[u].pop_back();
    if(a[u].empty()) return;
    sort(a[u].begin(), a[u].end(), [](const int& x, const int& y)
         {
             return a[x].size() > a[y].size();
         });
    for(int v: a[u]) DFS(v, u);
}

int Build(int u)
{
    int sum = 0;
    for(int v: a[u]) sum += Build(v);
    return max(0, sum + (int)a[u].size() - crew);
}

bool Chk(int mid)
{
     crew = mid;
     if(crew >= n) return 1;
     return Build(1) == 0;
}

void Enter()
{
     Cin(n);
     For(i, 2, n)
     {
         Cin(u, v);
         a[u].pb(v), a[v].pb(u);
     }
     DFS(1, 1);
}

void Solve()
{
     int low = 1, high = n;
     while(low <= high)
     {
         int mid = (low + high) >> 1;
         if(Chk(mid)) high = mid - 1;
         else low = mid + 1;
     }
     int res = n;
     Ford(i, low + 1, low - 1) if(Chk(i)) res = i;
     cout << res;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifdef Karma
    freopen(FileName".inp", "r", stdin);
    freopen(FileName".out", "w", stdout);
#endif // Karma

    Enter();
    Solve();

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10