Submission #549631

#	Time	Username	Problem	Language	Result	Execution time	Memory
549631		Theo830	Fountain Parks (IOI21_parks)	C++17	Compilation error	0 ms	0 KiB

parks

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
//void build(std::vector<int> u, std::vector<int> v, std::vector<int> a, std::vector<int> b);
ll dx[4] = {2,-2,0,0};
ll dy[4] = {0,0,2,-2};
map<ii,ll>mp;
ll p[200005];
ll find_par(ll a){
    if(p[a] == a){
        return a;
    }
    return p[a] = find_par(p[a]);
}
void enose(ll a,ll b){
    ll p1 = find_par(a);
    ll p2 = find_par(b);
    p[p1] = p2;
}
int construct_roads(std::vector<int> x, std::vector<int> y) {
    ll n = x.size();
    f(i,0,n){
        mp[ii(x[i],y[i])] = i+1;
        p[i+1] = i+1;
    }
    vector<int>u,v,a,b;
    f(i,0,n){
        f(j,0,4){
            ll X = x[i] + dx[j];
            ll Y = x[i] + dy[j];
            ll pos = mp[ii(X,Y)];
            if(pos && find_par(i+1) != find_par(pos)){
                enose(i+1,pos);
                u.pb(i+1);
                v.pb(pos);
            }
        }
    }
    a.assign(n-1,0);
    b.assign(n-1,0);
    if(u.size() != n-1){
        return 0;
    }
    mp.clear();
    map<ii,vll>ex;
    set<iii>s;
    f(i,0,n-1){
        ll A = (x[u[i]] + x[v[i]]) / 2;
        ll B = (y[u[i]] + y[v[i]]) / 2;
        if(A % 2 == 0){
            mp[ii(A+1,B)]++;
            mp[ii(A-1,B)]++;
            ex[ii(A+1,B)].pb(i);
            ex[ii(A-1,B)].pb(i);
        }
        else{
            mp[ii(A,B+1)]++;
            mp[ii(A,B-1)]++;
            ex[ii(A,B+1)].pb(i);
            ex[ii(A,B-1)].pb(i);
        }
    }
    for(auto x:mp){
        s.insert(iii(x.S,x.F));
    }
    while(!s.empty()){
        auto it = s.begin();
        for(auto z:ex[(*it).S]){
            if(a[z] == 0){
                a[z] = (*it).S.F;
                b[z] = (*it).S.S;
                break;
            }
        }
        s.erase((*it));
    }
    build(u,v,a,b);
    return 1;
}
/*
static void check(bool cond, string message) {
	if (!cond) {
		printf("%s\n", message.c_str());
		fclose(stdout);
		exit(0);
	}
}

static int n;
static bool build_called;
static int m;
static vector<int> _u, _v, _a, _b;
void build(vector<int> u, vector<int> v, vector<int> a, vector<int> b) {
	check(!build_called, "build is called more than once");
	build_called = true;
	m = u.size();
	check(int(v.size()) == m, "u.size() != v.size()");
	check(int(a.size()) == m, "u.size() != a.size()");
	check(int(b.size()) == m, "u.size() != b.size()");
	_u = u;
	_v = v;
	_a = a;
	_b = b;
}

int main() {
	assert(scanf("%d", &n) == 1);
	vector<int> x(n), y(n);
	for (int i = 0; i < n; i++) {
		assert(scanf("%d%d", &x[i], &y[i]) == 2);
	}
	fclose(stdin);

	build_called = false;
	const int possible = construct_roads(x, y);

	check(possible == 0 || possible == 1, "Invalid return value of construct_roads()");
	if (possible == 1) {
		check(build_called, "construct_roads() returned 1 without calling build()");
	} else {
		check(!build_called, "construct_roads() called build() but returned 0");
	}

	printf("%d\n", possible);
	if (possible == 1) {
		printf("%d\n", m);
		for (int j = 0; j < m; j++) {
			printf("%d %d %d %d\n", _u[j], _v[j], _a[j], _b[j]);
		}
	}
	fclose(stdout);
	return 0;
}
*/

Compilation message (stderr)

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:62:17: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
   62 |     if(u.size() != n-1){
      |        ~~~~~~~~~^~~~~~
parks.cpp:98:5: error: 'build' was not declared in this scope
   98 |     build(u,v,a,b);
      |     ^~~~~