mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
42 lines
943 B
C++
42 lines
943 B
C++
#include<iostream>
|
|
#include<algorithm>
|
|
#include<string>
|
|
using namespace std;
|
|
const int N = 300+10;
|
|
int s[N*N],g[N*N];
|
|
#define _cp(a,b) ((a)<=(b))
|
|
int _tmp[N*N];
|
|
int inv(int n,int* a){
|
|
int l=n>>1,r=n-l,i,j;
|
|
int ret=(r>1?(inv(l,a)+inv(r,a+l)):0);
|
|
for (i=j=0;i<=l;_tmp[i+j]=a[i],i++)
|
|
for (ret+=j;j<r&&(i==l||!_cp(a[i],a[l+j]));_tmp[i+j]=a[l+j],j++);
|
|
memcpy(a,_tmp,sizeof(int)*n);
|
|
return ret;
|
|
}
|
|
int main()
|
|
{
|
|
int n;
|
|
while(scanf("%d",&n)==1 && n)
|
|
{
|
|
int num=0;
|
|
bool flag=true;
|
|
for(int i=0;i<n*n;i++)
|
|
{
|
|
scanf("%d",&g[i]);
|
|
if(flag && g[i]!=0)
|
|
num++;
|
|
if(g[i]==0)
|
|
flag=false;
|
|
}
|
|
int temp=inv(n*n,g);
|
|
temp-=num;
|
|
if(!(n&1))
|
|
temp+=(n-1-(num/n));
|
|
if(temp&1)
|
|
puts("NO");
|
|
else puts("YES");
|
|
}
|
|
return 0;
|
|
}
|