Submission #119280

#	Time	Username	Problem	Language	Result	Execution time	Memory
119280		eriksuenderhauf	Flood (IOI07_flood)	C++11	100 / 100	156 ms	11360 KiB

flood

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
#define mem(a,v) memset((a), (v), sizeof (a))
#define enl printf("\n")
#define case(t) printf("Case #%d: ", (t))
#define ni(n) scanf("%d", &(n))
#define nl(n) scanf("%I64d", &(n))
#define nai(a, n) for (int i = 0; i < (n); i++) ni(a[i])
#define nal(a, n) for (int i = 0; i < (n); i++) nl(a[i])
#define pri(n) printf("%d\n", (n))
#define prl(n) printf("%I64d\n", (n))
#define pii pair<int, int>
#define pil pair<int, long long>
#define pll pair<long long, long long>
#define vii vector<pii>
#define vil vector<pil>
#define vll vector<pll>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef cc_hash_table<int,int,hash<int>> ht;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> oset;
const double pi = acos(-1);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
const int MAXN = 2e5 + 5;
const double eps = 1e-9;
int x[MAXN], y[MAXN], a[MAXN], b[MAXN], nxt[MAXN][4], vis[MAXN], mrk[MAXN][2];

/*
	3
2		0
	1
*/

int main() {
	priority_queue<pair<pii,int>> pq;
	int n, w;
	ni(n);
	for (int i = 1; i <= n; i++)
		scanf("%d %d", x + i, y + i);
	ni(w);
	for (int i = 1; i <= w; i++) {
		int u, v;
		scanf("%d %d", &u, &v);
		if (x[u] > x[v] || y[u] > y[v])
			swap(u, v);
		a[i] = u, b[i] = v;
		if (x[u] == x[v]) { // vertical
			nxt[u][3] = i;
			nxt[v][1] = i;
		} else { // horizontal
			nxt[u][0] = i;
			nxt[v][2] = i;
		}
		pq.push(mp(mp(x[v], -y[v]), i));
	}
	while (!pq.empty()) {
		int cur = pq.top().se; pq.pop();
		if (vis[cur])
			continue;
		int u = a[cur], dir = x[a[cur]] == x[b[cur]] ? 1 : 2;
		vi act;
		while (1) {
			int nx, ndir;
			for (int i = 0; i < 4; i++) {
				ndir = (dir + 3 + i) % 4;
				nx = nxt[u][ndir];
				if (nx > 0 && !vis[nx])
					break;
			}
			if (mrk[nx][ndir / 2])
				break;
			mrk[nx][ndir / 2] = 1;
			act.pb(nx);
			if (a[nx] == u)
				u = b[nx];
			else
				u = a[nx];
			dir = ndir;
		}
		for (int nx: act)
			vis[nx] = 1;
	}
	vi ans;
	for (int i = 1; i <= w; i++)
		if (mrk[i][0] > 0 && mrk[i][1] > 0)
			ans.pb(i);
	printf("%d\n",(int) ans.size());
	for (int i: ans)
		printf("%d\n", i);
    return 0;
}

Compilation message (stderr)

flood.cpp: In function 'int main()':
flood.cpp:9:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define ni(n) scanf("%d", &(n))
               ~~~~~^~~~~~~~~~~~
flood.cpp:48:2: note: in expansion of macro 'ni'
  ni(n);
  ^~
flood.cpp:50:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", x + i, y + i);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
flood.cpp:9:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define ni(n) scanf("%d", &(n))
               ~~~~~^~~~~~~~~~~~
flood.cpp:51:2: note: in expansion of macro 'ni'
  ni(w);
  ^~
flood.cpp:54:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

• 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: 9 / 9
• Subtask 13: 9 / 9
• Subtask 14: 9 / 9