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| #include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;
#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))
#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
using ll=long long;
struct dsu{
vector<int> fa,sz;
dsu(int n){
fa.resize(n+1),sz.resize(n+1);
for(int i=1;i<=n;++i)fa[i]=i,sz[i]=1;
}
int fnd(int x){
return fa[x]==x?x:fa[x]=fnd(fa[x]);
}
bool merge(int x ,int y){
int oa=fnd(x),ob=fnd(y);
if(oa!=ob){
fa[ob]=oa,sz[oa]+=sz[ob];
return true;
}
return false;
}
};
int tt,n,k,b[(int)1e5+9];
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cin>>tt;
while(tt--){
cin>>n>>k;
dsu d(n);
vector<vector<int>> g(n+1,vector<int>());
vector<int> dis(n+1,0);
bool same=true;
for(int i=1;i<=n;++i){
cin>>b[i];
d.merge(i,b[i]),g[i].push_back(b[i]);
same&=b[i]==i;
}
auto dfs=[&](auto self,int u,int fa,int dep)->ll{
dis[u]=dep;
ll res=0ll;
for(auto it:g[u]){
if(dis[it])res=max(res,dep-dis[it]+1ll);
else res=max(res,self(self,it,u,dep+1));
}
return res;
};
bool ok=true;
if(k==1&&!same)ok=false;
f(i,1,n)if(d.fnd(i)==i)ok&=dfs(dfs,i,0,1)==k;
cout<<(ok?"YES\n":"NO\n");
}
return 0;
}
|