Submission #1096146

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096146		Cadoc	Race (IOI11_race)	C++17	100 / 100	441 ms	73416 KiB

race

/*
    Author: Cadocx
    Codeforces: https://codeforces.com/profile/Kadoc
    VNOJ: oj.vnoi.info/user/Cadoc
*/

#include <bits/stdc++.h>
using namespace std;

// input/output
#define fastIO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define el cout << '\n'
//data type
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define piv pair<int, vector<int>>
#define vi vector<int>
#define vl vector<ll>
#define vc vector<char>
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return 1; }; return 0; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return 1; }; return 0; }
//STL
#define sz(x) (int)(x).size()
#define FOR(i,l,r) for(auto i = l; i <= r; i++)
#define FORD(i,r,l) for(auto i = r; i >= l; i--)
#define forin(i,a) for(auto i : a)
#define pb push_back
#define eb emplace_back
#define pf push_front
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
//bitmask
#define bitcnt(n) __builtin_popcount(n)
#define mask(i) (1 << (i))
#define bit(n, i) (((n) >> (i)) & 1)
#define set_on(n, i) ((n) | mask(i))
#define set_off(n, i) ((n) & ~mask(i))
//constant
#define maxN 200005
#define MOD 1000230007
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define base 31
#define Kadoc 0

int n, k;
int H[maxN][2], L[maxN];
int pos[maxN], p[maxN << 2][22], Timer = 0;
int h[maxN], d[maxN];
int sz[maxN], del[maxN];
vector<pii> g[maxN];
int f[1000005];
vector<int> V;
int Ans = INF;

void dfs(int u, int pr = -1){
    pos[u] = ++Timer;
    p[Timer][0] = u;
    for(auto [v, w]:g[u]) if(v != pr){
        h[v] = h[u] + 1;
        d[v] = d[u] + w;
        dfs(v, u);
        p[++Timer][0] = u;
    }
}

void dfs_sz(int u, int p = -1){
    sz[u] = 1;
    for(auto [v, w]:g[u]) if(v != p && !del[v]){
        dfs_sz(v, u);
        sz[u] += sz[v];
    }
}

int getMin(int u, int v){
    return (h[u] < h[v]? u:v);
}

int lca(int u, int v){
    int l = pos[u], r = pos[v];
    if(l > r) swap(l, r);

    int k = 31 - __builtin_clz(r-l+1);
    return getMin(p[l][k], p[r-mask(k)+1][k]);
}

int dist(int u, int v){
    return h[u] + h[v] - 2 * h[lca(u, v)];
}

int distW(int u, int v){
    return d[u] + d[v] - 2 * d[lca(u, v)];
}

void upd(int u, int root, int p = -1){
    int hu = dist(u, root), du = distW(u, root);
    if(k >= du){
        minimize(f[du], hu);
        V.pb(du);
    }

    for(auto [v, w]:g[u]) if(v != p && !del[v]) upd(v, root, u);
}

void get(int u, int root, int p = -1){
    int hu = dist(u, root), du = distW(u, root);
    if(k >= du) minimize(Ans, hu + f[k - du]);

    for(auto [v, w]:g[u]) if(v != p && !del[v]) get(v, root, u);
}

int centroid(int u, int p, int n){
    for(auto [v, w]:g[u]) if(v != p && !del[v] && sz[v] > n/2) return centroid(v, u, n);
    return u;
}

void cd(int u, int p = -1){
    dfs_sz(u);
    u = centroid(u, p, sz[u]);

    del[u] = 1;
    
    f[0] = 0;
    for(auto [v, w]:g[u]) if(!del[v]){
        get(v, u);
        upd(v, u);
    }

    for(int depth:V) f[depth] = INF;
    V.clear();

    for(auto [v, w]:g[u]) if(!del[v]) cd(v, u);
}

int best_path(int N, int K, int H[][2], int L[]){
    n = N; k = K;
    FOR(i, 0, n-2){
        int u = H[i][0], v = H[i][1], w = L[i];
        g[u].pb({v, w});
        g[v].pb({u, w});
    }

    dfs(1);

    for(int j=1; mask(j)<=Timer; ++j) for(int i=1; i+mask(j)-1<=Timer; ++i){
        p[i][j] = getMin(p[i][j-1], p[i+mask(j-1)][j-1]);
    }

    memset(f, 0x3f, sizeof f);
    cd(1);

    if(Ans >= INF) Ans = -1;
    return Ans;
}

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