codeforces 839b 之 Game of the Rows
2017-09-23 21:35
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B. Game of the Rows
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Daenerys Targaryen has an army consisting of k groups of soldiers, the i-th
group contains ai soldiers.
She wants to bring her army to the other side of the sea to get the Iron Throne. She has recently bought an airplane to carry her army through the sea. The airplane has nrows,
each of them has 8 seats. We call two seats neighbor, if they are in the same row and in seats {1, 2}, {3, 4}, {4, 5}, {5, 6} or {7, 8}.
![](http://codeforces.com/predownloaded/20/a1/20a11448a0afaf3655320120c369fcbc0e46769d.png)
A
row in the airplane
Daenerys Targaryen wants to place her army in the plane so that there are no two soldiers from different groups sitting on neighboring seats.
Your task is to determine if there is a possible arranging of her army in the airplane such that the condition above is satisfied.
Input
The first line contains two integers n and k (1 ≤ n ≤ 10000, 1 ≤ k ≤ 100) —
the number of rows and the number of groups of soldiers, respectively.
The second line contains k integers a1, a2, a3, ..., ak (1 ≤ ai ≤ 10000),
where ai denotes
the number of soldiers in the i-th group.
It is guaranteed that a1 + a2 + ... + ak ≤ 8·n.
Output
If we can place the soldiers in the airplane print "YES" (without quotes). Otherwise print "NO"
(without quotes).
You can choose the case (lower or upper) for each letter arbitrary.
Examples
input
output
input
output
input
output
input
output
Note
In the first sample, Daenerys can place the soldiers like in the figure below:
![](http://codeforces.com/predownloaded/68/af/68afdb222319f399071898ab865b5a9b11e8cd90.png)
In the second sample, there is no way to place the soldiers in the plane since the second group soldier will always have a seat neighboring to someone from the first group.
In the third example Daenerys can place the first group on seats (1, 2, 7, 8), and the second group an all the remaining seats.
In the fourth example she can place the first two groups on seats (1, 2) and (7, 8),
the third group on seats (3), and the fourth group on seats (5, 6).
分析:每行都是2 4 2的结构 先尝试中间的4,再尝试两边的2
AC代码如下:
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 100+10;
int a[maxn];
int main()
{
int n,k;
while(cin>>n>>k)
{
for(int i=0;i<k;i++)
cin>>a[i];
int s4=n;
int s2=2*n;
for(int i=0;i<k;i++)
{
int d=min(s4,a[i]/4);
s4-=d;
a[i]-=4*d;
}
s2+=s4;
for(int i=0;i<k;i++)
{
int d=min(s2,a[i]/2);
s2-=d;
a[i]-=2*d;
}
int s1=s4+s2;
for(int i=0;i<k;i++)
{
s1-=a[i];
}
cout<<(s1>=0?"YES":"NO")<<endl;
}
return 0;
}
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Daenerys Targaryen has an army consisting of k groups of soldiers, the i-th
group contains ai soldiers.
She wants to bring her army to the other side of the sea to get the Iron Throne. She has recently bought an airplane to carry her army through the sea. The airplane has nrows,
each of them has 8 seats. We call two seats neighbor, if they are in the same row and in seats {1, 2}, {3, 4}, {4, 5}, {5, 6} or {7, 8}.
![](http://codeforces.com/predownloaded/20/a1/20a11448a0afaf3655320120c369fcbc0e46769d.png)
A
row in the airplane
Daenerys Targaryen wants to place her army in the plane so that there are no two soldiers from different groups sitting on neighboring seats.
Your task is to determine if there is a possible arranging of her army in the airplane such that the condition above is satisfied.
Input
The first line contains two integers n and k (1 ≤ n ≤ 10000, 1 ≤ k ≤ 100) —
the number of rows and the number of groups of soldiers, respectively.
The second line contains k integers a1, a2, a3, ..., ak (1 ≤ ai ≤ 10000),
where ai denotes
the number of soldiers in the i-th group.
It is guaranteed that a1 + a2 + ... + ak ≤ 8·n.
Output
If we can place the soldiers in the airplane print "YES" (without quotes). Otherwise print "NO"
(without quotes).
You can choose the case (lower or upper) for each letter arbitrary.
Examples
input
2 2 5 8
output
YES
input
1 2 7 1
output
NO
input
1 2 4 4
output
YES
input
1 4 2 2 1 2
output
YES
Note
In the first sample, Daenerys can place the soldiers like in the figure below:
![](http://codeforces.com/predownloaded/68/af/68afdb222319f399071898ab865b5a9b11e8cd90.png)
In the second sample, there is no way to place the soldiers in the plane since the second group soldier will always have a seat neighboring to someone from the first group.
In the third example Daenerys can place the first group on seats (1, 2, 7, 8), and the second group an all the remaining seats.
In the fourth example she can place the first two groups on seats (1, 2) and (7, 8),
the third group on seats (3), and the fourth group on seats (5, 6).
分析:每行都是2 4 2的结构 先尝试中间的4,再尝试两边的2
AC代码如下:
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 100+10;
int a[maxn];
int main()
{
int n,k;
while(cin>>n>>k)
{
for(int i=0;i<k;i++)
cin>>a[i];
int s4=n;
int s2=2*n;
for(int i=0;i<k;i++)
{
int d=min(s4,a[i]/4);
s4-=d;
a[i]-=4*d;
}
s2+=s4;
for(int i=0;i<k;i++)
{
int d=min(s2,a[i]/2);
s2-=d;
a[i]-=2*d;
}
int s1=s4+s2;
for(int i=0;i<k;i++)
{
s1-=a[i];
}
cout<<(s1>=0?"YES":"NO")<<endl;
}
return 0;
}
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