#pragma GCC target("avx") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #include // #include // #include // #include // using namespace __gnu_pbds; // #include // namespace multiprecisioninteger = boost::multiprecision; // using cint=multiprecisioninteger::cpp_int; using namespace std; using ll=long long; #define double long double using datas=pair; using ddatas=pair; using tdata=pair; using vec=vector; using mat=vector; using pvec=vector; using pmat=vector; // using llset=tree,rb_tree_tag,tree_order_statistics_node_update>; #define For(i,a,b) for(i=a;i<(ll)b;++i) #define bFor(i,b,a) for(i=b,--i;i>=(ll)a;--i) #define rep(i,N) For(i,0,N) #define rep1(i,N) For(i,1,N) #define brep(i,N) bFor(i,N,0) #define brep1(i,N) bFor(i,N,1) #define all(v) (v).begin(),(v).end() #define allr(v) (v).rbegin(),(v).rend() #define vsort(v) sort(all(v)) #define vrsort(v) sort(allr(v)) #define uniq(v) vsort(v);(v).erase(unique(all(v)),(v).end()) #define endl "\n" #define eb emplace_back #define print(x) cout< ostream& operator<<(ostream& os,const pair& p){return os<<"("< ostream& operator<<(ostream& os,const vector& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os< ostream& operator<<(ostream& os,const set& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os< inline bool chmax(T& a,T b){bool x=a inline bool chmin(T& a,T b){bool x=a>b;if(x)a=b;return x;} #ifdef DEBUG void debugg(){cout<void debugg(const T& x,const Args&... args){cout<<" "<size;--i)modncrlistm[i-1]=modncrlistm[i]*i%mod; } return modncrlistp[n]*modncrlistm[r]%mod*modncrlistm[n-r]%mod; } ll modpow(ll a,ll n,ll m=mod){ ll res=1; while(n>0){ if(n&1)res=res*a%m; a=a*a%m; n>>=1; } return res; } ll gcd(ll a,ll b){if(!b)return abs(a);return (a%b==0)?abs(b):gcd(b,a%b);} ll lcm(ll a,ll b){return a/gcd(a,b)*b;} ll countdigits(ll n,ll k=10){ ll ans=0; while(n){n/=k;ans++;} return ans; } ll sumdigits(ll n,ll k=10){ ll ans=0; while(n){ans+=n%k;n/=k;} return ans; } class matrix{ mat a; ll H,W; public: matrix(mat& g):a(g){ H=g.size(); W=g[0].size(); } matrix(ll i,ll j):a(i,vec(j,0)){H=i;W=j;} matrix(ll n):a(n,vec(n,0)){H=W=n;} inline vec& operator [](int k){ return a.at(k); } // matrix operator =(matrix b){ // this->a.swap(b->a); // this->H=b.H; // this->W=b.W; // return (*this); // } matrix operator +=(matrix b){ ll i,j; rep(i,this->H)rep(j,this->W)(*this)[i][j]+=b[i][j]; return (*this); } matrix operator -=(matrix b){ ll i,j; rep(i,this->H)rep(j,this->W)(*this)[i][j]-=b[i][j]; return (*this); } matrix operator *=(matrix b){ ll i,j,k; assert(this->W==b.H); matrix c(this->H,b.W); rep(i,this->H)rep(j,b.W){ c[i][j]=0; rep(k,this->W)c[i][j]|=(*this)[i][k]&b[k][j]; } (*this)=c; return (*this); } matrix operator ^=(ll K){ assert(this->H==this->W); matrix c(this->H); ll i; rep(i,this->H)c[i][i]=1; if(K&1)c*=(*this); while(K){ K>>=1; (*this)*=(*this); if(K&1)c*=(*this); } this->a.swap(c.a); return (*this); } matrix operator +(matrix c){ return matrix(*this)+=c; } matrix operator -(matrix c){ return matrix(*this)-=c; } matrix operator *(matrix c){ return matrix(*this)*=c; } matrix operator ^(ll K){ return matrix(*this)^=K; } void out(){ for(auto x:a)output(x); } }; struct unionfind{ private: int maxN; vector par,treesize; public:unionfind(int N) :maxN(N),par(N),treesize(N,1){ for(int i=0;itreesize[y])swap(x,y); par[x]=y; treesize[y]+=treesize[x]; return true; } bool unite(pair v){ return unite(v.first,v.second); } bool parcheck(int x,int y){ return root(x)==root(y); } bool parcheck(pair v){ return parcheck(v.first,v.second); } int size(int x){ return treesize[root(x)]; } void clear(){ treesize.assign(maxN,1); for(int i=0;i> groups(){ vector> res(maxN); for(int i=0;i> res2; for(vector x:res){ if(x.size())res2.eb(x); } return res2; } }; bitset<2001> g[2001]; ll N,M,K,H,W,A,B,C,D; string s,t; ll ans; int main(){ startupcpp(); ll i,j; cin>>N>>K; rep(i,N){ string s; cin>>s; rep(j,N)g[i][j]=s[j]=='1'; } rep(i,N){ queue> que; vector dist(N*2,mod); que.emplace(0,0); while(!que.empty()){ int d,id,f; tie(d,id)=que.front();que.pop(); if(!chmin(dist[id],d))continue; f=1-id/N;id%=N; rep(j,N){ if(g[id][j]&&chmin(dist[j+f*N],d+2))que.emplace(d+1,j+f*N); } } int f=K&1; rep(j,N)if(dist[j+f*N]>K||dist[j+f*N]==mod){ printno; return 0; } } printyes; }