﻿ CodeForces 673D Bear and Two Paths（构造） - 鸿网互联

# CodeForces 673D Bear and Two Paths（构造）

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

int main()
{
int n,k,a,b,c,d;
vector<int>g;
scanf("%d%d",&n,&k);
scanf("%d%d%d%d",&a,&b,&c,&d);
if(n==4)
{
puts("-1");
return 0;
}
if (k<=n)
{
puts("-1");
return 0;
}
for (int i = 1;i<=n;i++)
{
if(i==a||i==b||i==c||i==d)
continue;
g.push_back(i);
}
printf("%d %d ",a,c);
for (int i = 0;i<g.size();i++)
printf("%d ",g[i]);
printf("%d %d\n",d,b);
printf("%d %d ",c,a);
for (int i = 0;i<g.size();i++)
printf("%d ",g[i]);
printf("%d %d\n",b,d);
}

Description

Bearland has n cities, numbered 1 through n. Cities are connected via bidirectional roads. Each road connects two distinct cities. No two roads connect the same pair of cities.

Bear Limak was once in a city a and he wanted to go to a city b. There was no direct connection so he decided to take a long walk, visiting each city exactly once. Formally:

• There is no road between a and b.
• There exists a sequence (path) of n distinct cities v1,?v2,?...,?vn that v1?=?avn?=?b and there is a road between vi and vi?+?1 for .

On the other day, the similar thing happened. Limak wanted to travel between a city c and a city d. There is no road between them but there exists a sequence of n distinct cities u1,?u2,?...,?un that u1?=?cun?=?d and there is a road between ui and ui?+?1 for .

Also, Limak thinks that there are at most k roads in Bearland. He wonders whether he remembers everything correctly.

Given nk and four distinct cities abcd, can you find possible paths (v1,?...,?vn) and (u1,?...,?un) to satisfy all the given conditions? Find any solution or print -1 if it's impossible.

Input

The first line of the input contains two integers n and k (4?≤?n?≤?1000n?-?1?≤?k?≤?2n?-?2) — the number of cities and the maximum allowed number of roads, respectively.

The second line contains four distinct integers abc and d (1?≤?a,?b,?c,?d?≤?n).

Output

Print -1 if it's impossible to satisfy all the given conditions. Otherwise, print two lines with paths descriptions. The first of these two lines should contain n distinct integers v1,?v2,?...,?vn where v1?=?a and vn?=?b. The second line should contain n distinct integersu1,?u2,?...,?un where u1?=?c and un?=?d.

Two paths generate at most 2n?-?2 roads: (v1,?v2),?(v2,?v3),?...,?(vn?-?1,?vn),?(u1,?u2),?(u2,?u3),?...,?(un?-?1,?un). Your answer will be considered wrong if contains more than k distinct roads or any other condition breaks. Note that (x,?y) and (y,?x) are the same road.

Sample Input

Input
7 11
2 4 7 3
Output
2 7 1 3 6 5 4
7 1 5 4 6 2 3
Input
1000 999
10 20 30 40
Output
-1

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