Submission #853545

#	Time	Username	Problem	Language	Result	Execution time	Memory
853545		YassirSalama	Race (IOI11_race)	C++17	0 / 100	4 ms	19548 KiB

race

#include "race.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <iomanip>
#include <cmath>
#include <limits>
#include <map>
#include <utility>
#include <cctype>
#include <string>
#include <cstring>
#include <stack>
#include <queue>
#include <functional>
#include <iterator>
using namespace std;
#define OVL(x,s) for(auto y:x) cout<<y<<s; cout<<"\n";
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__);
#define endl "\n"
#define pb push_back
#define F first
#define S second
#define ll long long
#define mod 1000000007
#define all(v) v.begin(),v.end()
const ll MAXN=2e5+100;
const ll MAXT=200;
const ll INF=1e9;
vector<pair<ll,ll>> v[MAXN];
ll n,k;
ll depth[MAXN];
map<ll,ll> mp[MAXN];
ll ans=INF;
ll dfs(ll node,ll par){
    if(v[node].size()==1&&v[node][0].F==par) return -1;
    // return -1;
    // mp[node].clear();
    for(auto x:v[node]){
        if(x.F==par) continue;
        ll a=dfs(x.F,node);
        // dbg(x.F,node,a);
        if(x.S>k) continue;
        if(x.S==k){
            ans=1;break;
        }
        if(a==-1){
            // dbg(x.F,node);
            mp[node][x.S]=1;
        }else{
            // dbg(node);
            map<ll,ll> newmp;
            for(auto & [key,value]:mp[x.F]){
                newmp[key+x.S]=value+1;
            }
            for(auto &[key,value]:newmp){
                ll target=k-key;
                // dbg(key,value,target,mp[node].count(target));
                if(target<0) continue;
                if(target==0){
                    ans=min(ans,value);
                    continue;
                }
                if(mp[node].count(target)){
                    ans=min(ans,mp[node][target]+value);
                }
            }
            for(auto [key,val]:mp[x.F]){
                 if(mp[node].count(key+x.S))
                     mp[node][key+x.S]=min(mp[node][key+x.S],val+1);
                 else mp[node][key+x.S]=val+1;
            }
        }
    }

    return 1;
}
int best_path(int N, int K, int H[][2], int L[])
{ 
    n=N;
    k=K;
    for(int i=0;i<n-1;i++){
    int a=H[i][0];
    int b=H[i][1];
    int c=L[i];
    v[a].pb({b,c});
    v[b].pb({a,c});
    }
    dfs(0,0);
    // dbg(ans);
    if(ans==INF)
        return -1;
    return ans;
}



#ifdef IOI

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