Submission #406108

#	Time	Username	Problem	Language	Result	Execution time	Memory
406108		amunduzbaev	Swapping Cities (APIO20_swap)	C++14	43 / 100	1299 ms	36708 KiB

swap

#include "swap.h"
#include "bits/stdc++.h"
using namespace std;
#define pb push_back
#define ff first
#define ss second
#define sz(x) (int)x.size()
#define int long long
template<class T> bool umin(T& a, const T b) { if(a > b) { a = b; return 1; } return 0; }
template<class T> bool umax(T& a, const T b) { if(a < b) { a = b; return 1; } return 0; }

const int NN = 1e5+5;
const int mod = 1e9+7;

int mx = 0, ok, res, d[NN], n, m;
vector<pair<int, int>> edges[NN];
vector<pair<int, int>> mm;
vector<int> tte[NN];
int tree = 0, cyc = 0, rope = 0;

void init(int32_t N, int32_t M,
	vector<int32_t> a, vector<int32_t> b, vector<int32_t> c) {
	n = N, m = M;
	for(int i=0;i<m;i++){
		edges[a[i]].pb({b[i], c[i]});
		edges[b[i]].pb({a[i], c[i]});
		tte[a[i]].pb(c[i]);
		tte[b[i]].pb(c[i]);
		mx = max(mx, (int)c[i]);
	} for(int i=0;i<n;i++) sort(tte[i].begin(), tte[i].end());
	tree = cyc = rope = 1;
	for(int i=0;i<m;i++) tree &= (min(a[i], b[i]) == 0);
	for(int i=0;i<n;i++) cyc &= (sz(edges[i]) == 2);
	for(int i=0;i<n;i++) rope &= (sz(edges[i]) <= 2);
}

int mn[NN], par[NN], bad[NN];
int mn2[NN];

int32_t getMinimumFuelCapacity(int32_t x, int32_t y) {
	if(cyc) return mx;
	if(rope) return -1;
	if(tree){
		if(x > y) swap(x, y);
		if(x == 0){
			if(y == mm[0].ss || y == mm[1].ss || y == mm[2].ss) return max({mm[0].ff, mm[1].ff, mm[2].ff});
			else return max({d[y], mm[0].ff, mm[1].ff});
		} else {
			if(n == 3) return -1;
			if((mm[0].ss == y || mm[1].ss == y) && (mm[0].ss == x || mm[1].ss == x)) return max({d[x], d[y], mm[2].ff});
			else if(x == mm[0].ss || y == mm[0].ss) return max({d[x], d[y], mm[1].ff});
			else return max({d[x], d[y], mm[0].ff});
		} 
	} 
	
	priority_queue<pair<int, int>> qq;
	qq.push({0, x});
	memset(mn, 127, sizeof mn);
	memset(mn2, 127, sizeof mn2);
	memset(bad, 0, sizeof bad);
	memset(par, 0, sizeof par);
	par[x] = -1, mn[x] = 0;
	while(!qq.empty()){
		auto u = qq.top(); qq.pop();
		if(mn[u.ss] < -u.ff) continue;
		for(auto x : edges[u.ss]) if(umin(mn[x.ff], max(mn[u.ss], x.ss))) par[x.ff] = u.ss, qq.push({-mn[x.ff], x.ff});
	} for(int i=0;i<n;i++) if(sz(tte[i]) >= 3) mn2[i] = tte[i][2], qq.push({-tte[i][2], i});
	while(!qq.empty()){
		auto u = qq.top(); qq.pop();
		if(mn2[u.ss] < -u.ff) continue;
		for(auto x : edges[u.ss]) if(umin(mn2[x.ff], max(mn2[u.ss], x.ss))) qq.push({-mn2[x.ff], x.ff});
	} int trr = mn[y], tt = y;
	vector<int> bads;
	while(~tt){
		bads.pb(tt);
		bad[tt] = 1;
		tt = par[tt];
	} int rr = mod;
	
	for(int i=0;i<n;i++){
		if(bad[i]){
			if(i == y || i == x) umin(rr, mn2[i]);
			else {
				int mn = mod;
				for(auto x : edges[i]){
					if(bad[x.ff]) continue;
					umin(mn, x.ss);
				} umin(rr, mn);
			}
		}
	} 
	
	int a = x, b = bads[sz(bads)-2];
	qq.push({0, x});
	for(int i=0;i<n;i++) mn[i] = mod;
	mn[x] = 0;
	while(!qq.empty()){
		auto u = qq.top(); qq.pop();
		if(mn[u.ss] < -u.ff) continue;
		for(auto x : edges[u.ss]){
			if((x.ff == a && u.ss == b) || (x.ff == b && u.ss == a)) continue;
			if(umin(mn[x.ff], max(mn[u.ss], x.ss))) qq.push({-mn[x.ff], x.ff});
		}
	} umin(rr, mn[y]); 
	a = y, b = bads[1];
	qq.push({0, x});
	for(int i=0;i<n;i++) mn[i] = mod;
	mn[x] = 0;
	while(!qq.empty()){
		auto u = qq.top(); qq.pop();
		if(mn[u.ss] < -u.ff) continue;
		for(auto x : edges[u.ss]){
			if((x.ff == a && u.ss == b) || (x.ff == b && u.ss == a)) continue;
			if(umin(mn[x.ff], max(mn[u.ss], x.ss))) qq.push({-mn[x.ff], x.ff});
		}
	} umin(rr, mn[y]); 
	
	
	if(rr == mod) return -1;
	return max(rr, trr);
}

• Subtask 1: 6 / 6
• Subtask 2: 0 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27