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  • Codeforces Round #520 (Div. 2)

    Codeforces Round #520 (Div. 2)

    https://codeforces.com/contest/1062

    A

     1 #include<bits/stdc++.h>
     2 using namespace std;
     3 #define lson l,mid,rt<<1
     4 #define rson mid+1,r,rt<<1|1
     5 #define sqr(x) ((x)*(x))
     6 #define pb push_back
     7 #define eb emplace_back
     8 #define maxn 100005
     9 #define eps 1e-8
    10 #define pi acos(-1.0)
    11 #define rep(k,i,j) for(int k=i;k<j;k++)
    12 typedef long long ll;
    13 typedef pair<int,int> pii;
    14 typedef pair<long long,int>pli;
    15 typedef pair<int,char> pic;
    16 typedef pair<pair<int,string>,pii> ppp;
    17 typedef unsigned long long ull;
    18 const long long mod=1e9+7;
    19 /*#ifndef ONLINE_JUDGE
    20         freopen("1.txt","r",stdin);
    21 #endif */
    22 
    23 int a[105];
    24 
    25 int main(){
    26     #ifndef ONLINE_JUDGE
    27      //   freopen("1.txt","r",stdin);
    28     #endif
    29     int n;
    30     cin>>n;
    31     if(n==1) {
    32         cout<<0<<endl;
    33         return 0;
    34     } 
    35     for(int i=1;i<=n;i++) cin>>a[i];
    36     a[0]=0,a[n+1]=1001;
    37     int ans=0,Max=0;
    38     for(int i=1;i<=n+1;i++){
    39         if(a[i]-a[i-1]==1){
    40             Max++;
    41         }
    42         else{
    43             ans=max(ans,Max-1);
    44             Max=0;
    45         }
    46         
    47     }
    48     ans=max(ans,Max-1);
    49     cout<<ans<<endl;
    50 }
    View Code

    B

     1 #include<bits/stdc++.h>
     2 using namespace std;
     3 #define lson l,mid,rt<<1
     4 #define rson mid+1,r,rt<<1|1
     5 #define sqr(x) ((x)*(x))
     6 #define pb push_back
     7 #define eb emplace_back
     8 #define maxn 100005
     9 #define eps 1e-8
    10 #define pi acos(-1.0)
    11 #define rep(k,i,j) for(int k=i;k<j;k++)
    12 typedef long long ll;
    13 typedef pair<int,int> pii;
    14 typedef pair<long long,int>pli;
    15 typedef pair<int,char> pic;
    16 typedef pair<pair<int,string>,pii> ppp;
    17 typedef unsigned long long ull;
    18 const long long mod=1e9+7;
    19 /*#ifndef ONLINE_JUDGE
    20         freopen("1.txt","r",stdin);
    21 #endif */
    22 
    23 int a[105];
    24 
    25 int main(){
    26     #ifndef ONLINE_JUDGE
    27      //   freopen("1.txt","r",stdin);
    28     #endif
    29     ll n;
    30     cin>>n;
    31     ll tmp=n;
    32     ll num=1;
    33     for(int i=2;i<=n;i++){
    34         if(tmp%i==0){
    35             num*=i;
    36             while(tmp%i==0){
    37                 tmp/=i;
    38             }
    39         }
    40     }
    41     ll ans=0;
    42     tmp=num;
    43     while(num%n){
    44         num*=num;
    45         ans++;
    46     } 
    47     cout<<tmp<<" "<<(ans+(num>n))<<endl;
    48 }
    View Code

    C

     数论+推公式

     1 #include<bits/stdc++.h>
     2 using namespace std;
     3 #define lson l,mid,rt<<1
     4 #define rson mid+1,r,rt<<1|1
     5 #define sqr(x) ((x)*(x))
     6 #define pb push_back
     7 #define eb emplace_back
     8 #define maxn 100005
     9 #define eps 1e-8
    10 #define pi acos(-1.0)
    11 #define rep(k,i,j) for(int k=i;k<j;k++)
    12 typedef long long ll;
    13 typedef pair<int,int> pii;
    14 typedef pair<long long,int>pli;
    15 typedef pair<int,char> pic;
    16 typedef pair<pair<int,string>,pii> ppp;
    17 typedef unsigned long long ull;
    18 const long long mod=1e9+7;
    19 /*#ifndef ONLINE_JUDGE
    20         freopen("1.txt","r",stdin);
    21 #endif */
    22 
    23 string str;
    24 ll sum[100005];
    25 
    26 ll pow_mul(ll a,ll b){
    27     ll ans=1;
    28     while(b){
    29         if(b&1)
    30             ans=ans*a%mod;
    31         b>>=1;
    32         a=a*a%mod;
    33     }
    34     return ans;
    35 }
    36 
    37 
    38 
    39 int main(){
    40     #ifndef ONLINE_JUDGE
    41      //   freopen("1.txt","r",stdin);
    42     #endif
    43     int n,q;
    44     cin>>n>>q;
    45     cin>>str;
    46     for(int i=0;i<n;i++){
    47         sum[i+1]=sum[i]+str[i]-'0';
    48     } 
    49     int l,r;
    50     while(q--){
    51         cin>>l>>r;
    52         ll ans=pow_mul(2,sum[r]-sum[l-1])-1;
    53         if(ans==-1) ans+=mod;
    54         ans=(ans+ans*(pow_mul(2,r-l+1+sum[l-1]-sum[r])-1+mod)%mod)%mod;
    55         cout<<ans<<endl;
    56     } 
    57 }
    View Code

    D

    数论

     1 #include<bits/stdc++.h>
     2 using namespace std;
     3 #define lson l,mid,rt<<1
     4 #define rson mid+1,r,rt<<1|1
     5 #define sqr(x) ((x)*(x))
     6 #define pb push_back
     7 #define eb emplace_back
     8 #define maxn 100005
     9 #define eps 1e-8
    10 #define pi acos(-1.0)
    11 #define rep(k,i,j) for(int k=i;k<j;k++)
    12 typedef long long ll;
    13 typedef pair<int,int> pii;
    14 typedef pair<long long,int>pli;
    15 typedef pair<int,char> pic;
    16 typedef pair<pair<int,string>,pii> ppp;
    17 typedef unsigned long long ull;
    18 const long long mod=1e9+7;
    19 /*#ifndef ONLINE_JUDGE
    20         freopen("1.txt","r",stdin);
    21 #endif */
    22 
    23 
    24 
    25 int main(){
    26     #ifndef ONLINE_JUDGE
    27      //   freopen("1.txt","r",stdin);
    28     #endif
    29     int n;
    30     cin>>n;
    31     ll ans=0;
    32     for(int i=2;i<=n;i++){
    33         for(int j=i+i;j<=n;j+=i){
    34             ans+=j/i;
    35         } 
    36     }
    37     cout<<ans*4<<endl;
    38 }
    View Code

    E

    lca+线段树+倍增

      1 #include<bits/stdc++.h>
      2 using namespace std;
      3 #define lson l,mid,rt<<1
      4 #define rson mid+1,r,rt<<1|1
      5 #define sqr(x) ((x)*(x))
      6 #define pb push_back
      7 #define eb emplace_back
      8 #define maxn 100005
      9 #define eps 1e-8
     10 #define pi acos(-1.0)
     11 #define rep(k,i,j) for(int k=i;k<j;k++)
     12 typedef long long ll;
     13 typedef pair<int,int> pii;
     14 typedef pair<long long,int>pli;
     15 typedef pair<int,char> pic;
     16 typedef pair<pair<int,string>,pii> ppp;
     17 typedef unsigned long long ull;
     18 const long long mod=1e9+7;
     19 /*#ifndef ONLINE_JUDGE
     20         freopen("1.txt","r",stdin);
     21 #endif */
     22 
     23 //int phi[maxn];
     24 
     25 vector<int>ve[maxn];
     26 
     27 int dep[maxn],parent[maxn][25],n,cnt;
     28 int Max[maxn<<2],Min[maxn<<2],id[maxn],s[maxn];
     29 
     30 void dfs(int now,int fa,int deep){
     31     dep[now]=deep;
     32     parent[now][0]=fa;
     33     s[now]=++cnt;
     34     id[cnt]=now;
     35     for(int i=0;i<ve[now].size();i++){
     36         dfs(ve[now][i],now,deep+1);
     37     }
     38 }
     39 
     40 void Init(){
     41     for(int j=1;j<19;j++){
     42         for(int i=1;i<=n;i++){
     43             parent[i][j]=parent[parent[i][j-1]][j-1];
     44         }
     45     }
     46 }
     47 
     48 int lca(int x,int y){
     49     if(dep[x]<dep[y]) swap(x,y);
     50     for(int i=18;i>=0;i--){
     51         if(dep[parent[x][i]]>=dep[y]){
     52             x=parent[x][i];
     53         }
     54     }
     55     if(x==y) return dep[x]-1;
     56     for(int i=18;i>=0;i--){
     57         if(parent[x][i]!=parent[y][i]){
     58             x=parent[x][i];
     59             y=parent[y][i];
     60         }
     61     }
     62     return dep[parent[x][0]]-1;
     63 }
     64 
     65 int query1(int L,int R,int l,int r,int rt){
     66     if(L<=l&&R>=r) return Max[rt];
     67     int mid=l+r>>1;
     68     int ans=0;
     69     if(L<=mid) ans=max(ans,query1(L,R,lson));
     70     if(R>mid) ans=max(ans,query1(L,R,rson));
     71     return ans;
     72 }
     73 
     74 int query2(int L,int R,int l,int r,int rt){
     75     if(L<=l&&R>=r) return Min[rt];
     76     int mid=l+r>>1;
     77     int ans=0x3f3f3f3f;
     78     if(L<=mid) ans=min(ans,query2(L,R,lson));
     79     if(R>mid) ans=min(ans,query2(L,R,rson));
     80     return ans;
     81 }
     82 
     83 void push_up(int rt){
     84     Max[rt]=max(Max[rt<<1],Max[rt<<1|1]);
     85     Min[rt]=min(Min[rt<<1],Min[rt<<1|1]);
     86 }
     87 
     88 void update(int L,int v,int l,int r,int rt){
     89     if(l==r){
     90         Max[rt]=Min[rt]=v;
     91         return;
     92     }
     93     int mid=l+r>>1;
     94     if(L<=mid) update(L,v,lson);
     95     else update(L,v,rson);
     96     push_up(rt);
     97 }
     98 
     99 int main(){
    100     #ifndef ONLINE_JUDGE
    101      //   freopen("1.txt","r",stdin);
    102     #endif
    103     std::ios::sync_with_stdio(false);
    104     int q;
    105     cin>>n>>q;
    106     int x,y;
    107     for(int i=2;i<=n;i++){
    108         cin>>x;
    109         ve[x].pb(i);
    110     }
    111     dfs(1,0,1);
    112     Init();
    113     for(int i=1;i<=n;i++){
    114         update(i,s[i],1,n,1);
    115     }
    116     while(q--){
    117         cin>>x>>y;
    118         int min1=query2(x,y,1,n,1);
    119         int max1=query1(x,y,1,n,1);
    120         update(id[min1],0x3f3f3f3f,1,n,1);
    121         int min2=query2(x,y,1,n,1);
    122         update(id[min1],min1,1,n,1);
    123         update(id[max1],0,1,n,1);
    124         int max2=query1(x,y,1,n,1);
    125         update(id[max1],max1,1,n,1);///?
    126         int ans1=lca(id[min1],id[max2]),ans2=lca(id[min2],id[max1]);
    127         if(ans1>=ans2){
    128             cout<<id[max1]<<" "<<ans1<<endl;
    129         }
    130         else{
    131             cout<<id[min1]<<" "<<ans2<<endl;
    132         }
    133     }
    134 
    135 }
    View Code

    F

    拓扑排序

    参考博客:https://www.cnblogs.com/yqgAKIOI/p/10012279.html

     1 #include<bits/stdc++.h>
     2 using namespace std;
     3 #define lson l,mid,rt<<1
     4 #define rson mid+1,r,rt<<1|1
     5 #define sqr(x) ((x)*(x))
     6 #define pb push_back
     7 #define eb emplace_back
     8 #define maxn 300005
     9 #define eps 1e-8
    10 #define pi acos(-1.0)
    11 #define rep(k,i,j) for(int k=i;k<j;k++)
    12 typedef long long ll;
    13 typedef pair<int,int> pii;
    14 typedef pair<long long,int>pli;
    15 typedef pair<int,char> pic;
    16 typedef pair<pair<int,string>,pii> ppp;
    17 typedef unsigned long long ull;
    18 const long long mod=1e9+7;
    19 /*#ifndef ONLINE_JUDGE
    20         freopen("1.txt","r",stdin);
    21 #endif */
    22 
    23 
    24 
    25 int n,m;
    26 int a[maxn],b[maxn],d[maxn],cnt[maxn];
    27 vector<int>ve[maxn];
    28 
    29 void topsort(int a[],int b[]){
    30     for(int i=0;i<n;i++) ve[i].clear();
    31     for(int i=0;i<m;i++){
    32         ve[a[i]].pb(b[i]);
    33         d[b[i]]++;
    34     }
    35     int num=n;
    36     queue<int>Q;
    37     for(int i=0;i<n;i++){
    38         if(!d[i]){
    39             Q.push(i);
    40             num--;
    41         }
    42     } 
    43     while(!Q.empty()){
    44         int now=Q.front();
    45         Q.pop();
    46         if(Q.empty()) cnt[now]+=num;
    47         else if(Q.size()==1){
    48             int tmp=1;
    49             for(int i=0,y=Q.front();i<ve[y].size();i++){
    50                 tmp&=(d[ve[y][i]]>1);
    51             }
    52             cnt[now]+=num*tmp;
    53         }    
    54         for(int i=0;i<ve[now].size();i++)
    55             if(!--d[ve[now][i]]){
    56                 Q.push(ve[now][i]);
    57                 num--;
    58             }
    59     }
    60     
    61 }
    62 
    63 int main(){
    64     #ifndef ONLINE_JUDGE
    65      //   freopen("1.txt","r",stdin);
    66     #endif
    67     std::ios::sync_with_stdio(false);
    68     cin>>n>>m;
    69     for(int i=0;i<m;i++){
    70         cin>>a[i]>>b[i];
    71         a[i]--,b[i]--;
    72     }
    73     topsort(a,b);
    74     topsort(b,a);
    75     int ans=0;
    76     for(int i=0;i<n;i++)
    77         ans+=(cnt[i]+2>=n);
    78     cout<<ans<<endl;
    79 
    80 }
    View Code
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  • 原文地址:https://www.cnblogs.com/Fighting-sh/p/10546724.html
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