| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 839098 | cpptowin | Race (IOI11_race) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
#define name "TASK"
#define fo(i,d,c) for(int i=d;i<=c;i++)
#define fod(i,c,d) for(int i=c;i>=d;i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout<<"\n";
#define int long long
#define inf 1000000000
#define pii pair<int,int>
#define vii vector<pii>
#define lb(x) x&-x
#define bit(i,j) ((i>>j)&1)
#define offbit(i,j) (i^(1<<j))
#define onbit(i,j) (i|(1<<j))
#define vi vector<int>
template <typename T1, typename T2> bool minimize(T1 &a, T2 b){if (a > b) {a = b; return true;} return false;}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b){if (a < b) {a = b; return true;} return false;}
using namespace std;
map<int,int> mp[maxn];
vii ke[maxn];
int a[maxn];
int b[maxn];
int n,k;
int ans = 1e18;
void dfs(int u,int par)
{
mp[u][0] = 0;
for(auto [v,w] : ke[u])
{
if(v == par) continue;
dfs(v,u);
a[v] = w;
b[v]++;
if(mp[u].size() < mp[v].size())
{
swap(mp[u],mp[v]);
swap(a[u],a[v]);
swap(b[u],b[v]);
}
for(auto it : mp[v])
{
int dist = it.fi + a[v];
if(mp[u].count(k - dist - a[u]))
ans = min(ans,mp[u][k - dist - a[u]] + it.se + b[u] + b[v]);
}
for(auto it : mp[v])
{
int dist = it.fi + a[v] - a[u];
if(mp[u].count(dist)) mp[u][dist] = min(mp[u][dist],it.se + b[v] - b[u]);
else mp[u][dist] = it.se + b[v] - b[u];
}
}
}
main()
{
if(fopen(name".inp","r"))
{
freopen(name".inp","r",stdin);
freopen(name".out","w",stdout);
}
ios_base::sync_with_stdio(false);cin.tie(NULL);
cin >> n >> k;
fo(i,1,n - 1)
{
int u,v,w;
cin >> u >> v >> w;
ke[u].pb(v,w);
ke[v].pb(u,w);
}
dfs(1,1);
cout << (ans == 1e18 ? -1 : ans);
}