Submission #1691973

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Source Code Expand

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <memory.h>

using namespace std;
typedef long long LL;
const int maxn = 800005;

int ehead[maxn],ecnt=1,deg[maxn];
struct edge {
	int u,v,next;
}edg[maxn];
void add(int u,int v) {
	edg[++ecnt]=(edge){u,v,ehead[u]};
	ehead[u]=ecnt;deg[u]++;
	edg[++ecnt]=(edge){v,u,ehead[v]};
	ehead[v]=ecnt;deg[v]++;
}
int n,a[maxn],b[maxn],w[maxn],vis[maxn],ra,rb;

void Euler(int u)
{
	for (int &j=ehead[u];j;j=edg[j].next)
	if (!vis[j>>1]) {
		vis[j>>1]=true;
		int v=edg[j].v;Euler(v);
		if (u==v+n) w[v]=-1;
		if (v==u+n) w[u]=1;
	}
}
int main()
{
	#ifdef Amberframe
		freopen("agc018f.in","r",stdin);
		freopen("agc018f.out","w",stdout);
	#endif
	scanf("%d",&n);
	for (int i=1;i<=n;i++) scanf("%d",&a[i]);
	for (int i=1;i<=n;i++) scanf("%d",&b[i]);
	for (int i=1;i<=n;i++) if (a[i]!=-1) add(i,a[i]);else ra=i;
	for (int i=1;i<=n;i++) if (b[i]!=-1) add(i+n,b[i]+n);else rb=i+n;
	add(0,ra);add(0,rb);
	for (int i=1;i<=n;i++)
		if ((deg[i]&1)!=(deg[i+n]&1)) {puts("IMPOSSIBLE");return 0;}
	puts("POSSIBLE");
	for (int i=1;i<=n;i++) if (deg[i]&1) add(i,i+n);
	Euler(0);for (int i=1;i<=n;i++) printf("%d ",w[i]);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:38:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:39:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for (int i=1;i<=n;i++) scanf("%d",&a[i]);
                                          ^
./Main.cpp:40:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for (int i=1;i<=n;i++) scanf("%d",&b[i]);
                                          ^

Judge Result