Submission #445186

#	Time	Username	Problem	Language	Result	Execution time	Memory
445186		JerryLiu06	Flood (IOI07_flood)	C++17	73 / 100	117 ms	11712 KiB

flood

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second
 
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert 
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#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 EACH(a, x) for (auto& a : x)
 
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
 
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; }
 
template<class T> void remDup(vector<T>& v) { sor(v); v.erase(unique(all(v)), v.end()); }
 
const int MOD = 1e9 + 7;
const int MX = 1e5 + 10;
const ll INF = 1e18;

int N, W; int X[MX], Y[MX], A[MX], B[MX]; vi P; pi adj[MX][4]; int deg[MX];

bool vis[MX][4]; set<int> allWalls; vi ans;

void DFS(int curPoint, int curDir) {
    vis[curPoint][curDir] = true;

    FOR(i, -1, 3) {
        int nDir = (curDir + i + 4) % 4;

        if (adj[curPoint][nDir].f != 0) {
            int nPoint = adj[curPoint][nDir].f;
            int curWall = adj[curPoint][nDir].s;

            if (!vis[nPoint][nDir]) {
                if (allWalls.count(curWall)) {
                    ans.pb(curWall);
                }
                else {
                    allWalls.insert(curWall);
                }
                DFS(nPoint, nDir);
            }
			break;
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    cin >> N; FOR(i, 1, N + 1) cin >> X[i] >> Y[i]; 

    P.rsz(N); iota(all(P), 1); sort(all(P), [&](int a, int b) { return X[a] == X[b] ? Y[a] < Y[b] : X[a] < X[b]; });

    cin >> W; F0R(i, W) {
        cin >> A[i] >> B[i]; 

        if (X[A[i]] == X[B[i]]) {
            if (Y[A[i]] > Y[B[i]]) swap(A[i], B[i]);

            adj[A[i]][1] = {B[i], i};
            adj[B[i]][3] = {A[i], i};
        }
        if (Y[A[i]] == Y[B[i]]) {
            if (X[A[i]] > X[B[i]]) swap(A[i], B[i]);

            adj[A[i]][0] = {B[i], i};
            adj[B[i]][2] = {A[i], i};
        }
        deg[A[i]]++, deg[B[i]]++;
    }
    EACH(point, P) {
        if (deg[point] == 0) continue;

        int DIR = 0; F0R(dir, 4) if (!vis[point][dir]) { DIR = dir; break; }

        DFS(point, DIR);

        EACH(i, allWalls) {
            if (X[A[i]] == X[B[i]]) {
                adj[A[i]][1] = {0, 0};
                adj[B[i]][3] = {0, 0};
            }
            if (Y[A[i]] == Y[B[i]]) {
                adj[A[i]][0] = {0, 0};
                adj[B[i]][2] = {0, 0};
            }
            deg[A[i]]--, deg[B[i]]--;
        }
        allWalls.clear();
    }
    cout << sz(ans) << "\n"; EACH(i, ans) cout << i + 1 << "\n";
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 3 / 3
• Subtask 5: 10 / 10
• Subtask 6: 3 / 3
• Subtask 7: 3 / 3
• Subtask 8: 3 / 3
• Subtask 9: 3 / 3
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9
• Subtask 12: 0 / 9
• Subtask 13: 0 / 9
• Subtask 14: 0 / 9