codeforces 468 B && 51nod 1557 两个集合

B. Two Sets

time limit per test
1 second

memory limit per test
256 megabytes

input
standard input

output
standard output

Little X has n distinct integers: p1, p2, ..., pn.
He wants to divide all of them into two sets A and B.
The following two conditions must be satisfied:

If number x belongs to set A,
then number a - x must also belong to set A.

If number x belongs to set B,
then number b - x must also belong to set B.

Help Little X divide the numbers into two sets or determine that it's impossible.

Input

The first line contains three space-separated integers n, a, b (1 ≤ n ≤ 105; 1 ≤ a, b ≤ 109).
The next line contains n space-separated distinct integers p1, p2, ..., pn (1 ≤ pi ≤ 109).

Output

If there is a way to divide the numbers into two sets, then print "YES" in the first line. Then print n integers: b1, b2, ..., bn (bi equals
either 0, or 1), describing
the division. If bi equals
to 0, then pi belongs
to set A, otherwise it belongs to set B.

If it's impossible, print "NO" (without the quotes).

Examples

input

4 5 9
2 3 4 5

output

YES
0 0 1 1

input

3 3 4
1 2 4

output

NO

Note

It's OK if all the numbers are in the same set, and the other one is empty.

题意：见http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1557

思路：map搞，开始想着遍历map两个map好像会出点问题？然后看的别人的用的记录下标的方法，要注意要优先考虑a、b中大的一方

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

const int N = 1e5+5;
int p
,myset
;
map<int,int> ma;
map<int,int> id;
int main()
{
int n,a,b;
cin >> n >> a >> b;
for(int i = 1;i <= n;i++)
scanf("%d",&p[i]),ma[p[i]] = 1,id[p[i]] = i;
sort(p+1,p+1+n);
int gre = max(a,b),les = min(a,b);
int ga,gb;
if(gre == a)
ga = 0,gb = 1;
else
ga = 1,gb = 0;
for(int i = 1;i <= n;i++)
{
if(ma[p[i]])
{
if(ma[gre-p[i]])
ma[p[i]] = ma[gre-p[i]] = 0,myset[id[p[i]]] = myset[id[gre-p[i]]] = ga;
else if(ma[les-p[i]])
ma[p[i]] = ma[les-p[i]] = 0,myset[id[p[i]]] = myset[id[les-p[i]]] = gb;
else
return 0 * printf("NO\n");
}
}

printf("YES\n");
for(int i = 1;i <= n;i++)
printf("%d ",myset[i]);
printf("\n");
return 0;
}

在cf上面看到一些大佬的并查集写的http://codeforces.com/contest/468/submission/7916826