今日SGU 5.7

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SGU 169

题意：求k位数里面有多少个是完美数，完美数的定义就是n是好数，n+1也是好数，那么n就是完美数，好数就是n%p(n)==0&&p(n)!=0，p(n)=a1*...*an

收获：找规律

#include<bits/stdc++.h>

#define de(x) cout<<#x<<"="<<x<<endl;

#define dd(x) cout<<#x<<"="<<x<<" ";

#define rep(i,a,b) for(int i=a;i<(b);++i)

#define repd(i,a,b) for(int i=a;i>=(b);--i)

#define repp(i,a,b,t) for(int i=a;i<(b);i+=t)

#define ll long long

#define mt(a,b) memset(a,b,sizeof(a))

#define fi first

#define se second

#define inf 0x3f3f3f3f

#define INF 0x3f3f3f3f3f3f3f3f

#define pii pair<int,int>

#define pdd pair<double,double>

#define pdi pair<double,int>

#define mp(u,v) make_pair(u,v)

#define sz(a) (int)a.size()

#define ull unsigned long long

#define ll long long

#define pb push_back

#define PI acos(-1.0)

#define qc std::ios::sync_with_stdio(false)

#define db double

#define all(a) a.begin(),a.end()

const int mod = 1e9+;

const int maxn = 1e5+;

const double eps = 1e-;

using namespace std;

bool eq(const db &a, const db &b) { return fabs(a - b) < eps; }

bool ls(const db &a, const db &b) { return a + eps < b; }

bool le(const db &a, const db &b) { return eq(a, b) || ls(a, b); }

ll gcd(ll a,ll b) { return a==?b:gcd(b%a,a); };

ll lcm(ll a,ll b) { return a/gcd(a,b)*b; }

ll kpow(ll a,ll b) {ll res=;a%=mod; if(b<) return ; for(;b;b>>=){if(b&)res=res*a%mod;a=a*a%mod;}return res;}

ll read(){

    ll x=,f=;char ch=getchar();

    while (ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}

    while (ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}

    return x*f;

}

int bit(ll n){

    int ret = ;

    while(n) n/=,ret++;

    return ret;

}

//ll p(ll n){

//    ll ret = 1;

////    dd(n)

//    while(n) ret*=(n%10),n/=10;

////    de(ret)

//    return ret;

//}

//bool check(ll n){

//    ll tmp = p(n);

//    if(tmp==0) return false;

//    if(n%tmp==0) return true;

//    return false;

//}

//bool ok(ll n){

//    if(check(n)&&check(n+1)) return true;

//    return false;

//}

int main(){

//    rep(i,1,1e9+1) {

//        if(ok(i)) {

//            dd(bit(i))de(i)

//        }

//    }

    qc;

    int k;

    cin>>k;--k;

    if(!k) printf("");

    else {

        if(k%==) printf("");

        else if(k%==) printf("");

        else printf("");

    }

    return ;

}

SGU 172

题意：m个人，每个人选择了两个考试，那么这两个考试不能在同一天考（n个考试），问你能不能满足所有的人

收获：dfs染色

#include<bits/stdc++.h>

#define de(x) cout<<#x<<"="<<x<<endl;

#define dd(x) cout<<#x<<"="<<x<<" ";

#define rep(i,a,b) for(int i=a;i<(b);++i)

#define repd(i,a,b) for(int i=a;i>=(b);--i)

#define repp(i,a,b,t) for(int i=a;i<(b);i+=t)

#define ll long long

#define mt(a,b) memset(a,b,sizeof(a))

#define fi first

#define se second

#define inf 0x3f3f3f3f

#define INF 0x3f3f3f3f3f3f3f3f

#define pii pair<int,int>

#define pdd pair<double,double>

#define pdi pair<double,int>

#define mp(u,v) make_pair(u,v)

#define sz(a) (int)a.size()

#define ull unsigned long long

#define ll long long

#define pb push_back

#define PI acos(-1.0)

#define qc std::ios::sync_with_stdio(false)

#define db double

#define all(a) a.begin(),a.end()

const int mod = 1e9+;

const int maxn = 2e2+;

const double eps = 1e-;

using namespace std;

bool eq(const db &a, const db &b) { return fabs(a - b) < eps; }

bool ls(const db &a, const db &b) { return a + eps < b; }

bool le(const db &a, const db &b) { return eq(a, b) || ls(a, b); }

ll gcd(ll a,ll b) { return a==?b:gcd(b%a,a); };

ll lcm(ll a,ll b) { return a/gcd(a,b)*b; }

ll kpow(ll a,ll b) {ll res=;a%=mod; if(b<) return ; for(;b;b>>=){if(b&)res=res*a%mod;a=a*a%mod;}return res;}

ll read(){

    ll x=,f=;char ch=getchar();

    while (ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}

    while (ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}

    return x*f;

}

//inv[1]=1;

//for(int i=2;i<=n;i++) inv[i]=(mod-mod/i)*inv[mod%i]%mod;

int n,m,u,v;

int a[maxn][maxn];

int col[maxn];

vector<int> ans;

void init(){

    mt(col,-);ans.clear();

    rep(i,,) rep(j,,) a[i][j] = ;

}

bool dfs(int u,int c){

    col[u] = c;

    rep(i,,n+){

        if(a[u][i]){

            a[u][i]=a[i][u]=;

            if(col[i]==-) { if(!dfs(i,c^)) return false; }

            else if(col[i]==c) return false;

        }

    }

    return true;

}

int main(){

    init();

    scanf("%d%d",&n,&m);

    rep(i,,m) scanf("%d%d",&u,&v),a[u][v]=a[v][u]=;

    rep(i,,n+) if(col[i]==-) {

        if(!dfs(i,)) return puts("no"),;

    }

    puts("yes");

    rep(i,,n+) if(col[i]) ans.pb(i);

    printf("%d\n",sz(ans));

    rep(i,,sz(ans)) printf("%d%c",ans[i]," \n"[i+==sz(ans)]);

    return ;

}