Submission #1197454

#	Time	Username	Problem	Language	Result	Execution time	Memory
1197454		adiyer	Swapping Cities (APIO20_swap)	C++20	100 / 100	327 ms	44916 KiB

swap

#include <bits/stdc++.h>

using namespace std;

const int MAXN = 2e5 + 11;

int n, m;
int p[MAXN], c[MAXN], sz[MAXN];

bool was[MAXN];

vector < int > cmp;
vector < int > g[MAXN], ver[MAXN], mn[MAXN], mx[MAXN];

vector < pair < int, pair < int, int > > > reb;

int get(int v, int t){
	if(p[v] == v || c[v] > t) return v;
	return get(p[v], t);
}

void unite(int a, int b, int t){
    int pa = get(a, t), pb = get(b, t), x = mn[pa].back();
    x -= (g[a].size() == 1), x -= (g[b].size() == 1);
    g[a].push_back(b), g[b].push_back(a);
    x += (g[a].size() == 1), x += (g[b].size() == 1);
    if(pa != pb){
        x += mn[pb].back();
        if(sz[pa] > sz[pb]) swap(pa, pb);
        sz[pb] += sz[pa], p[pa] = pb, c[pa] = t;
    }
    ver[pb].push_back(t), mn[pb].push_back(x), mx[pb].push_back(max({mx[pa].back(), mx[pb].back(), (int) g[a].size(), (int) g[b].size()}));
}

void init(int N, int M, vector < int > U, vector < int > V, vector < int > W){
    n = N, m = M;
    for(int i = 0; i < n; i++) p[i] = i, sz[i] = 1, ver[i].push_back(0), mn[i].push_back(0), mx[i].push_back(0);
    for(int i = 0; i < m; i++) reb.push_back({W[i], {U[i], V[i]}});
    sort(reb.begin(), reb.end());
    for(int i = 0; i < m; i++){
        auto [u, v] = reb[i].second;
        unite(u, v, i);
    }
}

void dfs(int v){
    was[v] = 1, cmp.push_back(v);
    for(int u : g[v])
        if(!was[u])
            dfs(u);
}

bool f(int x, int y, int t){
    if(get(x, t) != get(y, t)) return 0;
    x = get(x, t);
    int pos = upper_bound(ver[x].begin(), ver[x].end(), t) - ver[x].begin();
    return mx[x][pos - 1] > 2 || mn[x][pos - 1] == 0;
}

int getMinimumFuelCapacity(int X, int Y) {
    int l = -1, r = m;
    while(r - l > 1){
        int md = (l + r) / 2;
        if(f(X, Y, md)) r = md;
        else l = md;
    }
    if(r == m) return -1;
    return reb[r].first;
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27