Submission #227571

#	Time	Username	Problem	Language	Result	Execution time	Memory
227571		Benq	Ideal city (IOI12_city)	C++14	77 / 100	1093 ms	62856 KiB

city

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef double db; 
typedef string str; 
 
typedef pair<int,int> pi;
typedef pair<ll,ll> pl; 
typedef pair<db,db> pd; 
 
typedef vector<int> vi; 
typedef vector<ll> vl; 
typedef vector<db> vd; 
typedef vector<str> vs; 
typedef vector<pi> vpi;
typedef vector<pl> vpl; 
typedef vector<pd> vpd; 
 
#define mp make_pair 
#define f first
#define s second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#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 trav(a,x) for (auto& a: x)
 
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5; 
const ll INF = 1e18; 
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; 
 
template<class T> bool ckmin(T& a, const T& b) { 
	return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { 
	return a < b ? a = b, 1 : 0; } 
int pct(int x) { return __builtin_popcount(x); } 
int bit(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
int cdiv(int a, int b) { return a/b+!(a<0||a%b == 0); } // division of a by b rounded up, assumes b > 0 
 
// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);
 
template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }
 
template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }
 
// TO_STRING
#define ts to_string
template<class A, class B> str ts(pair<A,B> p);
template<class A> str ts(complex<A> c) { return ts(mp(c.real(),c.imag())); }
str ts(bool b) { return b ? "true" : "false"; }
str ts(char c) { str s = ""; s += c; return s; }
str ts(str s) { return s; }
str ts(const char* s) { return (str)s; }
str ts(vector<bool> v) { 
	bool fst = 1; str res = "{";
	F0R(i,sz(v)) {
		if (!fst) res += ", ";
		fst = 0; res += ts(v[i]);
	}
	res += "}"; return res;
}
template<size_t SZ> str ts(bitset<SZ> b) {
	str res = ""; F0R(i,SZ) res += char('0'+b[i]);
	return res; }
template<class T> str ts(T v) {
	bool fst = 1; str res = "{";
	for (const auto& x: v) {
		if (!fst) res += ", ";
		fst = 0; res += ts(x);
	}
	res += "}"; return res;
}
template<class A, class B> str ts(pair<A,B> p) {
	return "("+ts(p.f)+", "+ts(p.s)+")"; }
 
// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
	pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
	pr(h); if (sizeof...(t)) pr(" "); ps(t...); }
 
// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
	cerr << to_string(h); if (sizeof...(t)) cerr << ", ";
	DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 42
#endif
 
// FILE I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(string s = "") {
	unsyncIO();
	// cin.exceptions(cin.failbit); 
	// throws exception when do smth illegal
	// ex. try to read letter into int
	if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}
 
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 
 
const int mx = 100005;
 
/**
 * Description: Hash map with the same API as unordered\_map, but \tilde 3x faster.
 	* Initial capacity must be a power of 2 if provided.
 * Source: KACTL
 * Usage: ht<int,int> h({},{},{},{},{1<<16});
 */

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;

int N;
pi coor[mx]; // for an index, the coordinates
gp_hash_table<ll, int> tov; //for a coordinate, give the vertex index
 
bool visited[mx];
 
int currun = 0; //number of runs
int runnum[mx]; //run index for a point
vi runs[mx]; //indices in run i
int adj[mx][4];
 
void getrun(int ind){
	if(runnum[ind] != 0) return;
	currun++;
	while(adj[ind][2] != -1){
		ind = adj[ind][2];
	}
 
	/*
	while(tov.count(mp(xcor-1, ycor))){
		xcor--;
	}*/
 
	while(true){
		runnum[ind] = currun;
		runs[currun].pb(ind);
 
		if(adj[ind][0] == -1) break;
		ind = adj[ind][0];
	}
 
}
 
vector<pair<int, vpi>> borders[mx][2]; //for each run and direction (0 = below, 1 = above) run number, pair of coordinate indices on the border.
 
void getborders(){
 
	for(int i = 1; i <= currun; i++){
		vi a = runs[i];
 
		for(int j = 0; j < sz(a); j++){
			int ind = a[j];
			if(adj[ind][3] == -1){
				continue;
			}
			/*if(!tov.count(mp(xcor, ycor-1))){
				continue;
			}*/
			int vert = adj[ind][3];
 
			if(j > 0 && adj[vert][2] != -1){
				borders[i][0].bk.s.pb(mp(vert, ind));
				continue;
			}
			vpi c;
			c.pb(mp(vert, ind));
			borders[i][0].pb(mp(runnum[vert], c));
		}
		//ps(i, runs[i], borders[i][0]);
		cout.flush();
	}
 
 
 
	for(int i = 1; i <= currun; i++){
		vi a = runs[i];
		for(int j = 0; j < sz(a); j++){
			int ind = a[j];
			if(adj[ind][1] == -1){
				continue;
			}
			int vert = adj[ind][1];
			if(j > 0 && adj[vert][2] != -1){
				borders[i][1].bk.s.pb(mp(ind, vert));
				continue;
			}
			vpi c;
			c.pb(mp(ind, vert));
			borders[i][1].pb(mp(runnum[vert], c));
		}
	}
}
 
map<pi, int> diff; //pair of nodes, mode, # we add when we transition.
//pair of nodes is lower, higher
 
int getdiff(int mode, vpi *pairs, bool above){
	int run1 = runnum[(*pairs)[0].f];
	int run2 = runnum[(*pairs)[0].s];
	int rval = 0; // return value
	int bel, abo;
	if(above == 0){
		rval+=sz(runs[run1]);
		for(auto u: borders[run1][0]){
			if(u.f == run2) continue;
			rval+=getdiff(mode, &u.s, 0);
		}
		for(auto u: borders[run1][1]){
			if(u.f == run2) continue;
			rval+=getdiff(mode, &u.s, 1);
		}
		bel = rval;
		abo = N-bel;
	}
	else{
		rval+=sz(runs[run2]);
		for(auto u: borders[run2][0]){
			if(u.f == run1) continue;
			rval+=getdiff(mode, &u.s, 0);
		}
		for(auto u: borders[run2][1]){
			if(u.f == run1) continue;
			rval+=getdiff(mode, &u.s, 1);
		}
		abo = rval;
		bel = N-abo;
	}
	for(auto u: *pairs){
		diff[u] = bel-abo;
		diff[mp(u.s, u.f)] = -diff[u];
	}
	return rval;
}
 
void clearmem(){ //clear everything except tov, coor
	for(int i = 0; i < mx; i++){
		visited[i] = 0;
		runnum[i] = 0;
		runs[i].clear();
		borders[i][0].clear();
		borders[i][1].clear();
	}
	currun = 0;
}

const ll BASE = 3e9;

void swapcoors(){
	for(int i = 1; i <= N; i++){
		swap(coor[i].f, coor[i].s);
	}
	tov.clear();
	for(int i = 1; i <= N; i++){
		tov[BASE*coor[i].f+coor[i].s] = i;
	}
}
 
void genAdj(){
	for(int i = 1; i <= N; i++){
		for(int j = 0; j < 4; j++){
			adj[i][j] = -1;
		}
	}
	for(int i = 1; i <= N; i++){
		ll x = coor[i].f;
		ll y = coor[i].s;
		for(int j = 0; j < 4; j++){
          	auto it = tov.find(BASE*(x+xd[j])+(y+yd[j]));
          	if (it == end(tov)) continue;
			int to = it->s;
			adj[i][j] = to;
		}
	}
}
 
int cdsdist[mx];
 
ll calcdistsum(int st){
	for(int i = 1; i <= N; i++){
		cdsdist[i] = -1;
	}
	queue<pi> q;
	q.push(mp(st, 0));
	while(sz(q)){
		int node = q.front().f;
		int d = q.front().s;
		q.pop();
		if(cdsdist[node] != -1) continue;
		cdsdist[node] = d;
		for(int i = 0; i < 4; i++){
			if(adj[node][i] == -1) continue;
			int to = adj[node][i];
			q.push(mp(to, d+1));
		}
	}
	ll rval = 0;
	for(int i = 1; i <= N; i++){
		rval+=ll(cdsdist[i]);
	}
 
	return rval;
}
 
bool dfsvisit[mx];
ll dist[mx];
 
void dfs(int node, ll cursum = 0){
	if(dfsvisit[node] == 1) return;
	dfsvisit[node] = 1;
	if(node == 1){
		cursum = calcdistsum(1);
	}
	dist[node] = cursum;
	//dfs to the other nodes
	for(int i = 0; i < 4; i++){
		if(adj[node][i] == -1) continue;
		int to = adj[node][i];
		dfs(to, cursum+ll(diff[mp(node, to)]));
	}
}
 
int DistanceSum(int _N, int *x, int *y) {
	clock_t a = clock();
	
 
	N = _N;
 
	for(int i = 1; i <= N; i++){
		ll xval = ll(x[i-1]);
		ll yval = ll(y[i-1]);
		coor[i] = mp(xval, yval);
		tov[BASE*coor[i].f+coor[i].s] = i;
	}
	//#warning if using adj up here, uncomment line
	genAdj();
	/////////////////
 
	for(int i = 1; i <= N; i++){
		getrun(i);
	}
 
 
	/*for(int i = 1; i <= currun; i++){
		ps("i, runs[i]", i, runs[i]);
	}*/
 
	getborders();
 
	
 
	for(int i = 1; i <= currun; i++){
		if(sz(borders[i][1]) == 0) continue;
		pair<int, vpi> a = borders[i][1][0];
		getdiff(0, &a.s, 0);
		getdiff(0, &a.s, 1);
		break;
	}
	/////////////////
 
	clearmem();
 
	swapcoors(); //coor and tov
	genAdj();
 
	for(int i = 1; i <= N; i++){
		getrun(i);
	}
 
	getborders();
 
 
	for(int i = 1; i <= currun; i++){
		if(sz(borders[i][1]) == 0) continue;
		pair<int, vpi> a = borders[i][1][0];
		getdiff(0, &a.s, 0);
		getdiff(0, &a.s, 1);
		break;
	}
 
	swapcoors();
	genAdj();
	double b = double(clock()-a)/double(CLOCKS_PER_SEC);
	/*if(b > 0.5){
		return -1;
	}*/
	dfs(1);
	ll ans = 0;
	for(int i = 1; i <= N; i++){
		ans+=dist[i];
	}
 
	return int((ans/2) % 1000000000LL);
}
 
 
/*int main(){
	int _N;
	cin >> _N;
	int x[_N];
	int y[_N];
	for(int i = 0; i < _N; i++){
		cin >> x[i] >> y[i];
	}
 
	ps(DistanceSum(_N, x, y));
	
}*/

Compilation message (stderr)

city.cpp: In function 'int DistanceSum(int, int*, int*)':
city.cpp:419:9: warning: unused variable 'b' [-Wunused-variable]
  double b = double(clock()-a)/double(CLOCKS_PER_SEC);
         ^
city.cpp: In function 'void setIn(std::__cxx11::string)':
city.cpp:123:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
city.cpp: In function 'void setOut(std::__cxx11::string)':
city.cpp:124:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 0 / 23
• Subtask 4: 45 / 45