제출 #252998

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
252998		Kubin	경주 (Race) (IOI11_race)	C++17	21 / 100	3043 ms	10520 KiB

race

#include <bits/stdc++.h>

using namespace std;

vector<vector<pair<size_t, int>>> graph;

const int oo = INT_MAX / 3;
int& rd(map<int, int>& m, int key)
{
    auto it = m.find(key);
    if(it == m.end()) it = m.emplace_hint(it, key, +oo);
    return it->second;
}
void mini(map<int, int>& m, int key, int value)
{
    rd(m, key) = min(rd(m, key), value);
}

void dfs_map_paths(size_t u, int s, int d, map<int, int>& m,
                   size_t glock = SIZE_MAX, size_t lock = SIZE_MAX)
{
    if(d > +oo) return;
    mini(m, s, d);
    for(auto [v, w] : graph[u])
        if(v != lock and v != glock)
            dfs_map_paths(v, s + w, d + 1, m, glock, u);
}


int best_path(int _n, int k, int H[][2], int L[])
{
    const size_t n = _n;

    graph.resize(n);
    for(size_t i = 0; i < n - 1; i++)
    {
        graph[H[i][0]].emplace_back(H[i][1], L[i]);
        graph[H[i][1]].emplace_back(H[i][0], L[i]);
    }

    int result = +oo;
    for(size_t f = 0; f < n; f++)
    {
        map<int, int> pre = {{0, 0}};
        for(auto [v, w] : graph[f])
        {
            map<int, int> cur;
            dfs_map_paths(v, w, 1, cur, f);

            for(auto [s, d] : cur)
                result = min(result, d + rd(pre, k - s));
            for(auto [s, d] : cur)
                mini(pre, s, d);
        }

    }

    return result >= +oo ? -1 : result;
}


#ifdef XHOVA
#define MAX_N 500000

static int N, K;
static int H[MAX_N][2];
static int L[MAX_N];
static int solution;

inline
void my_assert(int e) {if (!e) abort();}

void read_input()
{
  int i;
  my_assert(2==scanf("%d %d",&N,&K));
  for(i=0; i<N-1; i++)
    my_assert(3==scanf("%d %d %d",&H[i][0],&H[i][1],&L[i]));
  my_assert(1==scanf("%d",&solution));
}

int main()
{
  int ans;
  read_input();
  ans = best_path(N,K,H,L);
  if(ans==solution)
    printf("Correct.\n");
  else
    printf("Incorrect. Returned %d, Expected %d.\n",ans,solution);

  return 0;
}
#endif

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57