Submission #890045

#	Time	Username	Problem	Language	Result	Execution time	Memory
890045		Kutan	Beads and wires (APIO14_beads)	C++14	28 / 100	1041 ms	6488 KiB

beads

// Cao Quang Hung
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>

using namespace std;
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<long long , long long>
#define vi vector<int>
#define vpii vector<pii>
#define SZ(x) ((int)(x.size()))
#define fi first
#define se second
#define IN(x,y) ((y).find((x))!=(y).end())
#define ALL(t) t.begin(),t.end()
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
#define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
#define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define dem(x) __builtin_popcount(x)
#define Mask(x) (1LL << (x))
#define BIT(x, i) ((x) >> (i) & 1)
#define ln '\n'
#define io_faster ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
///mt19937 rnd(time(0));

const int INF = 1e9 , mod = 1e9 + 7;

template <class T1, class T2>
inline T1 mul(T1& x, const T2 &k){ return x = (1LL * x * k) % mod; }

template <class T1 , class T2>
inline T1 pw(T1 x, T2 k){T1 res = 1; for (; k ; k >>= 1){ if (k & 1) mul(res, x); mul(x, x); } return res;}

template <class T>
inline bool minimize(T &x, const T &y){ if (x > y){x = y; return 1;} return 0; }

template <class T>
inline bool maximize(T &x, const T &y){ if (x < y){x = y; return 1;} return 0; }

template <class T>
inline void add(T &x , const T &y){ if ((x += y) >= mod) x -= mod; }

template <class T>
inline T product (const T &x , const T &y) { return 1LL * x * y % mod; }

#define PROB "a"
void file(){
    if(fopen(PROB".inp", "r")){
        freopen(PROB".inp","r",stdin);
        freopen(PROB".out","w",stdout);
    }
}
void sinh_(){
//    srand(time(0));
//    freopen(PROB".inp" , "w" , stdout);
//    int n;
}

typedef long long ll;
typedef double db;
const int N = 2e5 + 5;

vpii adj[N];
ll dp[N][2];
int n;

void readip(){
    cin >> n;
    REP(i, 2, n) {
        int u, v, c; cin >> u >> v >> c;
        adj[u].eb(v, c);
        adj[v].eb(u, c);
    }
}

void dfs_tree(int u, int p = -1) {
    if (adj[u].size() == 1 && p != -1) { // leaf
        dp[u][0] = 0;
        dp[u][1] = -1e18;
        return;
    }

    dp[u][0] = 0;
    ll sum = 0 , Max = -1e18;
    for (const auto &[v, w] : adj[u]) {
        if (v == p) continue;
        dfs_tree(v, u);
        dp[u][0] += max(w + dp[v][1], dp[v][0]);
        sum += max(w + dp[v][1] , dp[v][0]);
        maximize(Max, dp[v][0] + w - max(w + dp[v][1] , dp[v][0]));
    }   
    dp[u][1] = max(0LL, sum + Max);
    // for (const auto &[v, w] : adj[u]) if (v != p)
        // maximize(dp[u][1] , sum - max(w + dp[v][1] , dp[v][0]) + dp[v][0] + w);
}

void solve(){   
    ll res = 0;
    REP(i, 1, n) dfs_tree(i, -1), maximize(res, dp[i][0]);
    cout << res << ln;
}

int main(){
    sinh_();
    io_faster
    file();
    int t = 1;
//    cin >> t;
    while (t--){
        readip();
        solve();
    }
}

Compilation message (stderr)

beads.cpp: In function 'void readip()':
beads.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
beads.cpp:145:5: note: in expansion of macro 'REP'
  145 |     REP(i, 2, n) {
      |     ^~~
beads.cpp: In function 'void dfs_tree(int, int)':
beads.cpp:161:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  161 |     for (const auto &[v, w] : adj[u]) {
      |                      ^
beads.cpp: In function 'void solve()':
beads.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
beads.cpp:175:5: note: in expansion of macro 'REP'
  175 |     REP(i, 1, n) dfs_tree(i, -1), maximize(res, dp[i][0]);
      |     ^~~
beads.cpp: In function 'void file()':
beads.cpp:125:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |         freopen(PROB".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
beads.cpp:126:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  126 |         freopen(PROB".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 15 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43