Submission #564499

#	Time	Username	Problem	Language	Result	Execution time	Memory
564499		shrimb	Building Skyscrapers (CEOI19_skyscrapers)	C++17	8 / 100	682 ms	26096 KiB

skyscrapers

#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx,avx2,fma")

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

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

template<class x>
using ordered_set = tree<x, null_type,less<x>, rb_tree_tag,tree_order_statistics_node_update>;

#define int long long
#define endl '\n'
#define mod 1000000007
//\
#define mod 1686876991

int n, t;
int x[20], y[20];
int dx[] = {-1, 1, 0, 0, 1, 1, -1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, 1, -1};
int dp[20][2000];
set<pair<int,int>> pts;
set<pair<int,int>> placed;
pair<int,int> best[20][2000];

bool BAD (int x, int y) {
    queue<array<int,3>> q; // {x, y, dis}
    q.push({x, y, 0});
    while (q.size()) {
        auto [a, b, c] = q.front();
        q.pop();
        if (placed.count({a, b})) continue;
        if (c >= 10) return 0;
        for (int d = 0 ; d < 4 ; d++) {
            int u = a + dx[d];
            int v = b + dy[d];
            q.push({u, v, c + 1});
        }
    }
    return 1;
}

bool rec (int i, int mask) {
    // cerr << i << " " << mask << endl;
    if (dp[i][mask] != -1) return dp[i][mask];
    if (BAD(x[i], y[i])) {
        return dp[i][mask] = 0;
    }
    if (mask) {
        bool good = 0;
        for (int d = 0 ; d < 8 ; d++) {
            int u = x[i] + dx[d];
            int v = y[i] + dy[d];
            if (placed.count({u, v})) good = 1;
        }
        if (!good) return dp[i][mask] = 0;
    }
    placed.insert({x[i], y[i]});
    mask += (1 << i); 
    if (__builtin_popcount(mask) == n) {
        return 1;
    }
    for (int j = 0 ; j < n ; j++) {
        if (!(mask & (1 << j))) {
            if (rec(j, mask)) {
                best[i][mask&~(1<<i)] = {j, mask};
                return dp[i][mask] = 1;
            }
        }
    }
    placed.erase({x[i], y[i]});
    return dp[i][mask] = 0;
}

void follow (int i, int mask) {
    // cerr << i << " " << mask << endl;
    cout << i + 1 << endl;
    if (__builtin_popcount(mask) == n - 1) return;
    follow(best[i][mask].first, best[i][mask].second);
}

signed main () {
    memset(dp, -1, sizeof dp);
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> t;

    for (int i = 0 ; i < n ; i++) {
        cin >> x[i] >> y[i];
        pts.insert({x[i], y[i]});
    }

    if (n > 1) {
        for (int i = 0 ; i < n ; i++) {
            bool good = 0;
            for (int d = 0 ; d < 8 ; d++) {
                int u = x[i] + dx[d];
                int v = y[i] + dy[d];
                if (pts.count({u, v})) good = 1;
            }
            if (!good) {
                cout << "NO\n";
                return 0;
            }
        }
    }

    cout << "YES\n";
    for (int i = 0 ; i < n ; i++) {
        if (rec(i, 0)) {
            follow(i, 0);
        }
    }
}

Compilation message (stderr)

skyscrapers.cpp:17:1: warning: multi-line comment [-Wcomment]
   17 | //\
      | ^
skyscrapers.cpp: In function 'bool rec(long long int, long long int)':
skyscrapers.cpp:50:28: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   50 |         return dp[i][mask] = 0;
      |                ~~~~~~~~~~~~^~~
skyscrapers.cpp:59:39: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   59 |         if (!good) return dp[i][mask] = 0;
      |                           ~~~~~~~~~~~~^~~
skyscrapers.cpp:70:36: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   70 |                 return dp[i][mask] = 1;
      |                        ~~~~~~~~~~~~^~~
skyscrapers.cpp:75:24: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   75 |     return dp[i][mask] = 0;
      |            ~~~~~~~~~~~~^~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 14
• Subtask 3: 0 / 12
• Subtask 4: 0 / 17
• Subtask 5: 0 / 20
• Subtask 6: 0 / 10
• Subtask 7: 0 / 19