Submission #875888

#	Time	Username	Problem	Language	Result	Execution time	Memory
875888		hqminhuwu	Race (IOI11_race)	C++14	100 / 100	377 ms	112888 KiB

race

#include <bits/stdc++.h>
#define forr(_a,_b,_c) for(_a = (_b); _a <= (_c); ++_a)
#define ford(_a,_b,_c) for(_a = (_b) + 1; _a --> (_c);)
#define forf(_a,_b,_c) for(_a = (_b); _a < (_c); ++_a)
#define st first
#define nd second
#define ll long long
#define ull unsigned long long
#define pii pair <int,int>
#define pll pair <int,ll>
#define piii pair <int,pii>
#define vi vector <int>
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define file "test"
 
 
using namespace std;
const int N = 2e5 + 5;
const ll oo = 1e9;
const ll mod = 1e9 + 7;
 
map <int,ll> m[N];
vector <pll> a[N];
ll res, f[N], rk[N], dep[N];
ll k;
 
 
void dfs (int u, int p, ll c, int h) {
    m[u][c] = h;
	rk[u] = c;
	dep[u] = h;
	ll need = k + 2 * rk[u];
	for (pii v : a[u]) {
		if (v.st == p) continue;
		dfs (v.st, u, c + v.nd, h + 1);
		if (m[v.st].size() > m[u].size()) 
            swap(m[v.st], m[u]); 
 
		for (pll w : m[v.st]) 
			if (m[u].find(need - w.st) != m[u].end()) 
				res = min(res, m[u][need - w.st] + w.nd - 2 * dep[u]);
		
		for (pll w : m[v.st]) {
			if (m[u].find(w.st) == m[u].end()) 
				m[u].insert(w);
			 else  m[u][w.st] = min(m[u][w.st], w.nd);
		}
	}
}
int n,i,u,v,w;
int best_path (int nn, int kk, int edge[][2], int ww[]){
	res = oo;
    n = nn;
	k = kk;
    if (k == 1)
        return 0;
    forf (i,0,n - 1){
        u = edge[i][0];
		v = edge[i][1];
		w = ww[i];
        a[u].pb({v,w});
        a[v].pb({u,w});
    }
    dfs(0,0,0,0);
    return (res <= n - 1 ? res : -1);
}
 

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