Codeforces Round #596 (Div. 2, based on Technocup 2020 Elimination Round 2)

Forgetting Things

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 3e5+20;
const int MOD = 1e9+7;
int n;
int main() {
  int a,b;
  cin >> a >> b;
  if(a==b){cout << a << "0" << " " << b << "1" << endl;}
  else if(a+1==b){cout << a << " " << b << endl;}
  else if(a==9 && b == 1)cout << "9 10" << endl;
  else puts("-1");
}

TV Subscriptions (Easy Version)

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e5+20;
const int MOD = 1e9+7;
int n,k,d;
map<int,int>ma;
int num[MAXN];
int main() {
  int _;
  cin >> _;
  while (_--){
    cin >> n >> k >> d;
    ma.clear();
    int minn=d;
    for (int i = 0; i < n; ++i) {
      cin >> num[i];
      ma[num[i]]++;
      if(i >= d){
        ma[num[i-d]]--;
        if(ma[num[i-d]]==0){
          ma.erase(num[i-d]);
        }
      }
      if(i>=d-1){
        minn=min(minn,(int)ma.size());
      }
      //cout << "i:" << i << ":size:" << ma.size() << endl;
    }
    cout << minn << endl;
  }
}

TV Subscriptions (Hard Version)

 #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e5+20;
const int MOD = 1e9+7;
int n,k,d;
map<int,int>ma;
int num[MAXN];
int main() {
  int _;
  cin >> _;
  while (_--){
    cin >> n >> k >> d;
    ma.clear();
    int minn=d;
    for (int i = 0; i < n; ++i) {
      cin >> num[i];
      ma[num[i]]++;
      if(i >= d){
        ma[num[i-d]]--;
        if(ma[num[i-d]]==0){
          ma.erase(num[i-d]);
        }
      }
      if(i>=d-1){
        minn=min(minn,(int)ma.size());
      }
      //cout << "i:" << i << ":size:" << ma.size() << endl;
    }
    cout << minn << endl;
  }
}

p-binary

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e5+20;
const int MOD = 1e9+7;
ll n,k;
int loglen(ll i){
  int len=0;
  while(i){
    i >>= 1;
    len++;
    //cout << i << endl;
  }
  return len;
}
int renum(ll i){
  int len=0;
  while (i){
    if(i&1)len++;
    i >>= 1;
  }
  return len;
}
int main() {
  cin >> n >> k;
  int lenn=loglen(n);
  int lenn2=loglen(n-lenn*k);
  for (int i = 0; i < 30; ++i) {
    n-=k;
    if(n<=0){
      puts("-1");
      return 0;
    }
    if(i+1>n && k>=0){
      puts("-1");return 0;
    }
    int rn = renum(n);
    //cout << rn << "rn" << endl;
    if(rn <= i+1){
      cout << i+1 << endl;return 0;
    }
  }
  puts("-1");
  return 0;
}

Power Products

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5+20;
const int MOD = 1e9+7;
#define coutdebug(i) {cout<<"(i)"<<(i)<<endl;}
int n,k;
ll num[MAXN];
map<int,ll>ma,mf;
vector<int>vec;
ll cpow(ll i,int b=k){
  if(b==0)return 1;
  ll ans = i;
  if(i==1)return i;
  for (int j = 1; j < b; ++j) {
    ans*=i;
    if(ans > 1e10)return -1;
  }
  return ans;
}
ll fun(ll a, int b=k )
{
  ll r = 1;
  ll base = a;
  while( b)
  {
    if(b & 1){
      r *= base;
      if(r > 1e10)return -1;
      if(b==1)return r;
    }
    base *= base; //注意：a^{2^7}=a^{2^6} * a^{2^6} ，而不是 a^{2^7}=a^{2^6} * a ，所以這是對的。
    if(base > 1e10)return -1;
    b /= 2;//與b=b>>1相同
  }
  return r;
}
 
int factor(int n)
{
  int remain=1;
  for(int i=2,a=1; i*i<=n; i+=a,a=2)
  {
    int cnt=0;
    if(n%i==0) while(n%i==0)
    {
      cnt++;
      n /= i;
    }
    remain*=cpow(i,cnt%k);
  }
  if(n > 1)
    remain*=n;
  return remain;
}
int main() {
  scanf("%d%d",&n,&k);
  ll min0=MAXN,max0=0;
  ll max1,min1;
  for (int i = 0; i < n; ++i) {
    int cur;
    scanf("%d",&cur);
    cur=factor(cur);
    //cout << cur << endl;
    num[cur]++;
    ma[cur]++;
    max0=max(max0,(ll)cur);
    min0=min(min0,(ll)cur);
  }
  if(k==2){
    ll ans=0;
    for (int i = 1; i <= max0; ++i) {
      if(num[i])
        ans+=num[i]*(num[i]-1)/2;
    }
    cout << ans << endl;
    return 0;
  }
  {
    auto it = ma.end();
    it--;
    max0=it->first;
    if(it->second==1){
      it--;
      max1=it->first;
    }
    else max1=it->first;
    auto it1=ma.begin();
    min0=it1->first;
    if(it1->second==1){
      it1++;
      min1=it1->first;
    }
    else min1=it1->first;
  }
 
  for (auto mit=ma.begin();mit!=ma.end();mit++)
    vec.push_back(mit->first);
 
 
  ll ans=0;
  for (ll i = 1;i<=max0; ++i) {
    //cout << "i:" << i << endl;
    ll powk=fun(i);
    if(powk==-1)break;
    if(powk<min0*min1)continue;
    if(powk>max0*max1)break;
    auto it = std::lower_bound (vec.begin(), vec.end(), (powk/max0));
    //cout << "lowerbound:" << it->first << endl;
    for (; it!=vec.end(); ++it){
      ll a=(*it);
      if(a*a>powk)break;
      if(powk%a!=0)continue;
      ll b=powk/a;
      if(b > max0)continue;
      //cout << a << " a b " << b << endl;
      if(a==b){
        ans+=(num[a])*(num[a]-1)/2;
        break;
      }
      if (num[b]){
        ans+=(num[a])*(num[b]);
      }
    }
    //cout << "ans" << ans << endl;
  }
  cout << ans << endl;
}
/*
 2 1
 1 1
 
 
 9 2
 2 4 6 8 10 11 11 12 16
 
 8 2
 2 4 6 8 10 11 11 12
 */

Rock Is Push

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 2e3+20;
const ll MOD = 1e9+7;
char s[MAXN][MAXN];
ll d[MAXN][MAXN];
ll d2[MAXN][MAXN][2];
ll sum[MAXN][MAXN][2];
int vertical[MAXN][MAXN],horizontal[MAXN][MAXN];
#define coutdebug(i) {cout<<"debug"<<(i)<<endl;}
int n,m;
int main() {
  scanf("%d%d",&n,&m);
  for(int i=1;i<=n;i++)scanf("%s",s[i]+1);
  if(s[1][1]=='R'||s[n][m]=='R'){puts("0");return 0;}
  for (int i = 1; i <= m; ++i)
    for (int j = 1; j <= n; ++j)
      vertical[i][j]=(vertical[i][j-1]+(s[n-j+1][i]=='R'?1:0));
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m; ++j)
    {horizontal[i][j]=(horizontal[i][j-1]+(s[i][m-j+1]=='R'?1:0));}
  d[1][1]=d2[1][1][0]=d2[1][1][1]=sum[1][1][0]=sum[1][1][1]=1;
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= m; ++j) {
      if(i == 1 && j == 1)continue;
      int a = m+1-j;
      int idx = lower_bound(horizontal[i]+1,horizontal[i]+m+1,a)-(horizontal[i]+1);
      int idx2=m-idx;
      if(idx2==j)d2[i][j][1]=0;
      else d2[i][j][1]=(d[i][j-1]-d[i][idx2]+d2[i][idx2][0]);
 
      //d2[i][j][1]=0;
      //for (int k = idx2; k <= j-1; ++k)d2[i][j][1]=(d2[i][j][1]+d2[i][k][0])%MOD;
      d2[i][j][1]=(sum[i][j-1][0]-sum[i][min(idx2-1,j-1)][0]+MOD)%MOD;
 
 
      int b=n+1-i;
      idx = lower_bound(vertical[j]+1,vertical[j]+n+1,b)-(vertical[j]+1);
      int idx3=n-idx;
      if(idx3==i)d2[i][j][0]=0;
      else d2[i][j][0]=(d[i-1][j]-d[idx3][j]+d2[idx3][j][1]);
 
      //d2[i][j][0]=0;
      //for (int k = idx3; k <= i-1; ++k)d2[i][j][0]=(d2[i][j][0]+d2[k][j][1])%MOD;
      d2[i][j][0]=(sum[i-1][j][1]-sum[min(idx3-1,i-1)][j][1]+MOD)%MOD;
 
      sum[i][j][1]=(d2[i][j][1]+sum[i-1][j][1])%MOD;
      sum[i][j][0]=(d2[i][j][0]+sum[i][j-1][0])%MOD;
      d[i][j]=(d2[i][j][0]+d2[i][j][1])%MOD;
 
 
//      cout << i << " i j " << j << endl;
//      cout << "idx2 " << idx2 << endl;
//      cout << "idx3 " << idx3 << endl;
//      cout << "d[i][j] " << d[i][j] << endl;
//      cout << "d[i][j][0] " << d2[i][j][0] << endl;
//      cout << "d[i][j][1] " << d2[i][j][1] << endl;
//      cout << "sum[i][j][1] " << sum[i][j][1] << endl;
//      cout << "sum[i][j][0] " << sum[i][j][0] << endl;
    }
  }
  cout << (d[n][m])%MOD << endl;
}
 
/*
 5 2
 ..
 .R
 ..
 .R
 ..
 
 5 3
 ...
 .R.
 ...
 .R.
 ...
 
 2 3
 ...
 .R.
 
 
 2 3
 .R.
 .R.
 
 2 3
 .R.
 R..
 
 5 3
 ...
 .R.
 R.R
 .R.
 ...
 
 2 2
 ..
 R.
 
 3 2
 ..
 R.
 ..
 
 2 4
 .R..
 .R..
 
 3 4
 ....
 .RR.
 ....
 
 
 */

Tree Factory

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5+20;
const ll MOD = 1e9+7;
#define coutdebug(i) {cout<<"debug"<<(i)<<endl;}
struct Node{
  int v,d;
  bool operator <(Node n){
    return d > n.d;
  }
};
vector<Node>vec[MAXN];
vector<int>num,cut;
int n;
int depth(int u){
  if(vec[u].size()==0)return 0;
  int maxn=0;
  for (auto &c : vec[u]) {
    c.d = depth(c.v);;
    maxn=max(maxn,c.d);
  }
  return maxn+1;
}
void dfs(int u,int app){
  if(app>=0)cut.push_back(app);
  for (int i = 0;i < vec[u].size();i++) {
    int v = vec[u][i].v;
    //cout << u << " u v " << v << endl;
    //cout << " d " << vec[u][i].d << endl;
    if(!i)dfs(v,app);
    else dfs(v,vec[u][i-1].v);
  }
  num.push_back(u);
}
int main() {
  scanf("%d",&n);
  for (int i = 1; i < n; ++i) {
    int cur;scanf("%d",&cur);
    vec[cur].push_back(Node{i,0});
  }
  depth(0);
  for (int i = 0; i < n; ++i)
    sort(vec[i].begin(),vec[i].end());
  dfs(0,-1);
  for (int i = 0; i < n; ++i)printf("%d ",num[n-i-1]);
  //for (int i = 0; i < n; ++i)printf("%d ",num[i]);
  puts("");
  cout << cut.size() << endl;
  for (int i = cut.size()-1; i >= 0; --i)
    printf("%d ",cut[i]);
 
}
 
/*
 6
 0 0 1 3 2
 
 10
 0 1 1 3 0 5 6 7 7
 
 */