Submission #121962

#	Time	Username	Problem	Language	Result	Execution time	Memory
121962		turbat	Aliens (IOI07_aliens)	C++14	Compilation error	0 ms	0 KiB

aliens

#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define N 100005

int n, w, k, cnt;
pair <int, int> wall[N][4];
pair <pair <int, int>, int > p[N];
bool vis[2 * N], brok[2 * N], stacked[N];

int dfs(int dir, int u){
	if (stacked[u]) return u;
	stacked[u] = 1;
	int t = dir + 3;
	t %= 4;
	while (t != (dir + 2) % 4){
		if (!vis[wall[u][t].S]) {
			vis[wall[u][t].S] = 1;
			int cyc = dfs(t, wall[u][t].F);
			if (cyc != -1){
				brok[wall[u][t].S] = 1;
				cnt--;
				stacked[u] = 0;
				if (cyc != u) return cyc;
			}
		}
		t++;
		t %= 4;
	}
	stacked[u] = 0;
	return -1;
}

int main (){
	vis[0] = 1;
	cin >> n;
	for (int i = 1;i <= n;i++) {
		p[i].S = i;
		cin >> p[i].F.F >> p[i].F.S;
		pos[i] = p[i].F;
	}
	cin >> w;
	for (int i = 1;i <= w;i++){
		int a, b;
		cin >> a >> b;
		if (p[a] > p[b]) swap(a, b);
		if (p[a].F.F == p[b].F.F){
			wall[a][2].F = b, wall[b][0].F = a;
			wall[a][2].S = wall[b][0].S = i;
		}
		else {
			wall[a][1].F = b, wall[b][3].F = a;
			wall[a][1].S = wall[b][3].S = i;
		}
	}
	sort (p + 1, p + n + 1);
	for (int i = 1;i <= n;i++) dfs(1, p[i].S);
	cout << w - k<< endl;
	for (int i = 1;i <= w;i++)
		if (!brok[i])
			cout << i << endl;
}

Compilation message (stderr)

aliens.cpp: In function 'int main()':
aliens.cpp:41:3: error: 'pos' was not declared in this scope
   pos[i] = p[i].F;
   ^~~
aliens.cpp:41:3: note: suggested alternative: 'pow'
   pos[i] = p[i].F;
   ^~~
   pow