Submission #936534

#	Time	Username	Problem	Language	Result	Execution time	Memory
936534		hqminhuwu	Race (IOI11_race)	C++14	100 / 100	1032 ms	60268 KiB

race

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef pair <int,pii> piii;

#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 pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"

const int Nn = 5e5 + 5;
const int oo = 1e9;
const ll mod = 1e9 + 7;

vector <pii> a[Nn];
int sz[Nn], del[Nn], ans, k, par[Nn];
map <int, int> m;

int dfs (int u, int p){
    sz[u] = 1;
    for (pii t : a[u]){
        int v = t.st;
        if (v != p && !del[v])
            sz[u] += dfs(v, u);
    }
    return sz[u];
}

int get (int u, int p, int nsz){
    for (pii t : a[u]){
        int v = t.st;
        if (v != p && !del[v] && sz[v] * 2 > nsz)
            return get(v, u, nsz);
    }
    return u;
}

void calc (int u, int p, int dep, int dis, bool keep){
    if (dis > k) return;
    if (!keep)
        ans = min (ans, dep - m[k - dis] + oo);
    else m[dis] = max (m[dis], oo - dep);
    for (pii t : a[u]){
        int v = t.st, w = t.nd;
        if (v != p && !del[v])
            calc(v, u, dep + 1, dis + w, keep);
    }
}

// m[i] = oo - dep[i];
void build (int u, int p){
    int ct = get(u, u, dfs(u, u));
    par[ct] = p;
    del[ct] = 1;

    m.clear();
    m[0] = oo;

    for (pii t : a[ct]){
        int v = t.st, w = t.nd;
        if (!del[v]){
            calc(v, ct, 1, w, 0);
            calc(v, ct, 1, w, 1);
        }
    }

    for (pii t : a[ct]){
        int v = t.st;
        if (!del[v]){
            build(v, ct);
        }
    }
}

int i, n, u, v, w;

int best_path (int nn, int kk, int edge[][2], int ww[]){
	ans = 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});
    }
    build(0, -1);
    return (ans <= n - 1 ? ans : -1);
}
/*



*/

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