AtCoder Regular Contest 080

手贱去开了abc，这么无聊。直接arc啊

C - 4-adjacent

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Time limit : 2sec / Memory limit : 256MB

Score : 400 points

Problem Statement

We have a sequence of length N, a=(a1,a2,…,aN). Each ai is a positive integer.

Snuke's objective is to permute the element in a so that the following condition is satisfied:

• For each 1≤i≤N−1, the product of ai and ai+1 is a multiple of 4.

Determine whether Snuke can achieve his objective.

Constraints

• 2≤N≤105
• ai is an integer.
• 1≤ai≤109

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Input

Input is given from Standard Input in the following format:

N
a1 a2 … aN

Output

If Snuke can achieve his objective, print Yes; otherwise, print No.

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Sample Input 1

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3
1 10 100

Sample Output 1

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Yes

One solution is (1,100,10).

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Sample Input 2

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4
1 2 3 4

Sample Output 2

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No

It is impossible to permute a so that the condition is satisfied.

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Sample Input 3

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3
1 4 1

Sample Output 3

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Yes

The condition is already satisfied initially.

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Sample Input 4

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2
1 1

Sample Output 4

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No

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Sample Input 5

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6
2 7 1 8 2 8

Sample Output 5

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Yes

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给你一个序列，通过你的安排让这个序列满足相邻两个数的乘积是4的倍数，如果有奇数的话,而且4的倍数个数+1还比奇数多，没有2的倍数，比如1 4 1就是成立的，

2的倍数很多，这些放哪都行，只要奇数和4的倍数能凑就行

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+5;
int a[N];
int main()
{
    int n;
    cin>>n;
    int cnt4=0,cnt2=0;
    for(int i=0; i<n; i++)
    {
        cin>>a[i];
        a[i]%=4;
        if(a[i]==0)
            cnt4++;
        else if(a[i]==2)
            cnt2++;
    }
    int cnt=n-cnt2-cnt4;
    if(cnt2)
    {
        if(cnt4>=cnt){
            cout<<"Yes";
            return 0;
        }
    }
    else
    {
        if(cnt4&&(cnt4+1>=cnt)){
            cout<<"Yes";
            return 0;
        }
    }
    cout<<"No";
    return 0;
}

D - Grid Coloring

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Time limit : 2sec / Memory limit : 256MB

Score : 400 points

Problem Statement

We have a grid with H rows and W columns of squares. Snuke is painting these squares in colors 1, 2, …, N. Here, the following conditions should be satisfied:

• For each i (1≤i≤N), there are exactly ai squares painted in Color i. Here, a1+a2+…+aN=HW.
• For each i (1≤i≤N), the squares painted in Color i are 4-connected. That is, every square painted in Color i can be reached from every square painted in Color i by repeatedly traveling to a horizontally or vertically adjacent square painted in Color i.

Find a way to paint the squares so that the conditions are satisfied. It can be shown that a solution always exists.

Constraints

• 1≤H,W≤100
• 1≤N≤HW
• ai≥1
• a1+a2+…+aN=HW

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Input

Input is given from Standard Input in the following format:

H W
N
a1 a2 … aN

Output

Print one way to paint the squares that satisfies the conditions. Output in the following format:

c11 … c1W
:
cH1 … cHW

Here, cij is the color of the square at the i-th row from the top and j-th column from the left.

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Sample Input 1

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2 2
3
2 1 1

Sample Output 1

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1 1
2 3

Below is an example of an invalid solution:

1 2
3 1

This is because the squares painted in Color 1 are not 4-connected.

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Sample Input 2

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3 5
5
1 2 3 4 5

Sample Output 2

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1 4 4 4 3
2 5 4 5 3
2 5 5 5 3

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Sample Input 3

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1 1
1
1

Sample Output 3

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1

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我的做法莫名wa，换了个做法ac，也差不到原因，反正注意下就好

就是给你n个数，代表第几个数有几个，他们必须是联通的，特判题

#include <bits/stdc++.h>
using namespace std;
vector<int>a[1005];
int main()
{
    int h,w;
    cin>>h>>w;
    int n;
    cin>>n;
    int f=0;
    for(int i=0; i<n; i++)
    {
        int x;
        scanf("%d",&x);
        for(int j=0;j<x;j++)
            a[f/w].push_back(i+1),f++;
    }
 
    for(int i=0; i<h; i++)
    {
        if(i&1)reverse(a[i].begin(),a[i].end());
        printf("%d",a[i][0]);
        for(int j=1; j<w; j++)
            printf(" %d",a[i][j]);
        printf("
");
    }
    return 0;
}

E - Young Maids

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Time limit : 2sec / Memory limit : 256MB

Score : 800 points

Problem Statement

Let N be a positive even number.

We have a permutation of (1,2,…,N), p=(p1,p2,…,pN). Snuke is constructing another permutation of (1,2,…,N), q, following the procedure below.

First, let q be an empty sequence. Then, perform the following operation until p becomes empty:

• Select two adjacent elements in p, and call them x and y in order. Remove x and y from p (reducing the length of p by 2), and insert x and y, preserving the original order, at the beginning of q.

When p becomes empty, q will be a permutation of (1,2,…,N).

Find the lexicographically smallest permutation that can be obtained as q.

Constraints

• N is an even number.
• 2≤N≤2×105
• p is a permutation of (1,2,…,N).

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Input

Input is given from Standard Input in the following format:

N
p1 p2 … pN

Output

Print the lexicographically smallest permutation, with spaces in between.

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Sample Input 1

Copy

4
3 2 4 1

Sample Output 1

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3 1 2 4

The solution above is obtained as follows:

p	q
(3,2,4,1)	()
↓	↓
(3,1)	(2,4)
↓	↓
()	(3,1,2,4)

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Sample Input 2

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2
1 2

Sample Output 2

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1 2

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Sample Input 3

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8
4 6 3 2 8 5 7 1

Sample Output 3

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3 1 2 7 4 6 8 5

The solution above is obtained as follows:

p	q
(4,6,3,2,8,5,7,1)	()
↓	↓
(4,6,3,2,7,1)	(8,5)
↓	↓
(3,2,7,1)	(4,6,8,5)
↓	↓
(3,1)	(2,7,4,6,8,5)
↓	↓
()	(3,1,2,7,4,6,8,5)

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每次取两个数，然后把这两个相邻数放到q里，使生成的q字典序最小

这个涉及到区间查询，可以用RMQor线段树。但是那两个数要怎么维护呢，用优先队列？

然后怎么做呢？卿学姐代码做法%一波