Submission #397415

#	Time	Username	Problem	Language	Result	Execution time	Memory
397415		JerryLiu06	Race (IOI11_race)	C++11	43 / 100	3082 ms	30148 KiB

race

#include <bits/stdc++.h>
#include "race.h"
 
using namespace std;
 
using ll = long long;
using db = long double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second
 
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
 
const int MOD = 1e9 + 7;
const int MX = 2e5 + 5;
const ll INF = 1e18;
 
int N, K, ans = MOD; vpi adj[200010]; int sub[200010]; bool vis[200010]; unordered_map<int, int> cur;
 
void DFS1(int X, int P) { 
    sub[X] = 1; EACH(Y, adj[X]) if (Y.f != P && !vis[Y.f]) { DFS1(Y.f, X); sub[X] += sub[Y.f]; } 
}
int getCent(int X, int P, int S) { 
    EACH(Y, adj[X]) if (Y.f != P && !vis[Y.f] && sub[Y.f] > S / 2) return getCent(Y.f, X, S); return X;
}
void DFS2(int X, int P, bool upd, int dist, int depth) {
    if (dist > K) return ; 
    
    if (upd) { if (cur.count(dist)) cur[dist] = min(cur[dist], depth); else cur[dist] = depth; }
    else { if (cur.count(K - dist)) ans = min(ans, cur[K - dist] + depth); }
 
    EACH(Y, adj[X]) if (Y.f != P && !vis[Y.f]) DFS2(Y.f, X, upd, dist + Y.s, depth + 1);
}
void decomp(int X) {
    DFS1(X, 0); int C = getCent(X, 0, sub[X]); vis[C] = true; cur.clear(); cur[0] = 0;
 
    EACH(Y, adj[C]) if (!vis[Y.f]) { DFS2(Y.f, C, false, Y.s, 1); DFS2(Y.f, C, true, Y.s, 1); }
 
    EACH(Y, adj[C]) if (!vis[Y.f]) decomp(Y.f);
}
int best_path(int _N, int _K, int H[][2], int L[]) {
    N = _N; K = _K; FOR(i, 0, N - 1) { 
        int A = H[i][0] + 1; int B = H[i][1] + 1; 
        
        adj[A].pb({B, L[i]}), adj[B].pb({A, L[i]});
    }
    decomp(1); return (ans == MOD ? -1 : ans);
}

Compilation message (stderr)

race.cpp: In function 'int getCent(int, int, int)':
race.cpp:42:20: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   42 | #define EACH(a, x) for (auto& a : x)
      |                    ^~~
race.cpp:54:5: note: in expansion of macro 'EACH'
   54 |     EACH(Y, adj[X]) if (Y.f != P && !vis[Y.f] && sub[Y.f] > S / 2) return getCent(Y.f, X, S); return X;
      |     ^~~~
race.cpp:54:95: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   54 |     EACH(Y, adj[X]) if (Y.f != P && !vis[Y.f] && sub[Y.f] > S / 2) return getCent(Y.f, X, S); return X;
      |                                                                                               ^~~~~~

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