42 lines
943 B
C++
42 lines
943 B
C++
#include<iostream>
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#include<algorithm>
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#include<string>
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using namespace std;
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const int N = 300+10;
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int s[N*N],g[N*N];
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#define _cp(a,b) ((a)<=(b))
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int _tmp[N*N];
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int inv(int n,int* a){
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int l=n>>1,r=n-l,i,j;
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int ret=(r>1?(inv(l,a)+inv(r,a+l)):0);
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for (i=j=0;i<=l;_tmp[i+j]=a[i],i++)
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for (ret+=j;j<r&&(i==l||!_cp(a[i],a[l+j]));_tmp[i+j]=a[l+j],j++);
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memcpy(a,_tmp,sizeof(int)*n);
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return ret;
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}
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int main()
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{
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int n;
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while(scanf("%d",&n)==1 && n)
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{
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int num=0;
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bool flag=true;
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for(int i=0;i<n*n;i++)
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{
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scanf("%d",&g[i]);
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if(flag && g[i]!=0)
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num++;
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if(g[i]==0)
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flag=false;
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}
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int temp=inv(n*n,g);
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temp-=num;
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if(!(n&1))
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temp+=(n-1-(num/n));
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if(temp&1)
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puts("NO");
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else puts("YES");
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}
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return 0;
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}
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