Hướng dẫn giải của Con Voi


Chỉ dùng lời giải này khi không có ý tưởng, và đừng copy-paste code từ lời giải này. Hãy tôn trọng người ra đề và người viết lời giải.
Nộp một lời giải chính thức trước khi tự giải là một hành động có thể bị ban.

Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

Code mẫu của flashmt

uses math;
const fi='';
      maxn=300000;
      z=1000000007;
var n,maxc,re:longint;
    a,b,f,g,d:array[1..maxn] of longint;

procedure sort(l,r:longint);
var i,j,x,y,t:longint;
begin
     i:=l; j:=r; x:=a[(i+j) shr 1]; y:=b[(i+j) shr 1];
     repeat
           while (a[i]<x) or ((a[i]=x) and (b[i]>y)) do i:=i+1;
           while (a[j]>x) or ((a[j]=x) and (b[j]<y)) do j:=j-1;
           if i<=j then
           begin
                t:=a[i]; a[i]:=a[j]; a[j]:=t;
                t:=b[i]; b[i]:=b[j]; b[j]:=t;
                i:=i+1; j:=j-1;
           end;
     until i>j;
     if i<r then sort(i,r);
     if l<j then sort(l,j);
end;

procedure sortt(l,r:longint);
var i,j,x,y:longint;
begin
     i:=l; j:=r; x:=b[(i+j) shr 1];
     repeat
           while b[i]<x do i:=i+1;
           while b[j]>x do j:=j-1;
           if i<=j then
           begin
                y:=b[i]; b[i]:=b[j]; b[j]:=y;
                y:=d[i]; d[i]:=d[j]; d[j]:=y;
                i:=i+1; j:=j-1;
           end;
     until i>j;
     if i<r then sortt(i,r);
     if l<j then sortt(l,j);
end;

procedure edit;
var i:longint;
begin
     maxc:=1; a[d[1]]:=1;
     for i:=2 to n do
     begin
          if b[i]>b[maxc] then
          begin
               maxc:=maxc+1;
               b[maxc]:=b[i];
          end;
          a[d[i]]:=maxc;
     end;
end;

procedure rf;
var i:longint;
begin
     read(n);
     for i:=1 to n do
     begin
          read(a[i],b[i]);
          d[i]:=i;
     end;
     sort(1,n);
     sortt(1,n);
     edit;
end;

function calc(x:longint;var num:longint):longint;
var r:longint;
begin
     num:=0; r:=0;
     while x>0 do
     begin
          if f[x]=r then
          begin
               num:=num+g[x];
               if num>=z then num:=num-z;
          end;
          if f[x]>r then
          begin
               r:=f[x]; num:=g[x];
          end;
          x:=x-x and (-x);
     end;
     calc:=r;
end;

procedure add(x,val,num:longint);
begin
     while x<=maxc do
     begin
          if val<f[x] then exit;
          if val=f[x] then
          begin
               g[x]:=g[x]+num;
               if g[x]>=z then g[x]:=g[x]-z;
          end
          else
          begin
               f[x]:=val; g[x]:=num;
          end;
          x:=x+x and (-x);
     end;
end;

procedure pr;
var i,x,val,num:longint;
begin
     for i:=1 to n do
     begin
          x:=a[i];
          val:=calc(x-1,num);
          if num=0 then num:=1;
          add(x,val+1,num);
     end;
     val:=calc(maxc,num);
     writeln(val);
     writeln(num);
end;

begin
     assign(input,fi); reset(input);
     rf;
     pr;
     close(input);
end.

Code mẫu của happyboy99x

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<vii> vvii;
typedef vector<int> vi;
typedef vector<vi> vvi;

#define sz(a) int((a).size())
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define tr(c,i) for(typeof((c).begin()) i = (c).begin(), _e = (c).end(); i != _e; ++i)
#define present(c,x) ((c).find(x) != (c).end())
#define cpresent(c,x) (find(all(c),x) != (c).end())
#define rep(i,n) for(int i = 0, _n = (n); i < _n; ++i)
#define repd(i,n) for(int i = (n)-1; i >= 0; --i )
#define fo(i,a,b) for(int i = (a), _b = (b); i <= _b; ++i)
#define fod(i,a,b) for(int i = (a), _b = (b); i >= _b; --i)

#define INF 1000000010
#define MOD 1000000007
#define N

vii P; //point
vi last, cnt; //cnt[i] = so cach nhay do dai i
vvii L;
int n;

void update( int i, int y, int add ) {
    cnt[i] = (cnt[i] + add) % MOD;
    L[i].pb(ii(y, (L[i].back().se + add) % MOD));
    last[i] = y;
}

void enter() {
    scanf("%d",&n);
    rep(i,n) {
        int x, y;
        scanf("%d%d",&x,&y);
        P.pb(ii(x,y));
    }
}

bool cmp(const ii &a, const ii &b) {
    return a.fi < b.fi || a.fi == b.fi && a.se > b.se;
}

void solve() {
    sort(all(P),cmp);
    L.resize(n+1); last.resize(n+1); cnt.resize(n+1);
    fill(all(last), INF); tr(L, it) it->pb(ii(INF, 0));
    update(0, -INF, 1);
    int best = 0;
    tr(P, it) {
        int A = lower_bound(all(last), it->se) - last.begin() - 1;
        /*typeof(L[0].rend()) B = lower_bound(rall(L[A]), ii(it->se, -INF));
        update(A+1, it->se, (cnt[A] - B->se) % MOD);*/
        update(A+1, it->se, (cnt[A] - lower_bound(rall(L[A]), ii(it->se, -INF))->se) % MOD);
        best = max(best, A+1);
    }
    printf("%d\n%d\n", best, (L[best].back().se + MOD) % MOD);
}

int main() {
#ifndef ONLINE_JUDGE
    freopen( "input.txt", "r", stdin );
    //freopen( "output.txt", "w", stdout );
#endif
    enter();
    solve();
    return 0;
}

Code mẫu của RR

//Written by RR

{$MODE OBJFPC}

uses math;
const
  FINP          =       '';
  FOUT          =       '';
  MAXN          =       300111;
  base          =       1000000007;

var
  f1,f2         :       text;
  n,d           :       longint;
  x,y,f,reg     :       array[0..MAXN] of longint;
  last,sl,ind   :       array[1..MAXN] of longint;

procedure openF;
    begin
      assign(f1,FINP); reset(f1);
      assign(f2,FOUT); rewrite(f2);
    end;

procedure closeF;
    begin
      close(f1);
      close(f2);
    end;

procedure inp;
    var
      i:longint;
    begin
      read(f1,n);
      for i:=1 to n do
        read(f1,x[i],y[i]);
    end;

procedure swap(var a,b:longint); inline;
    var
      tmp:longint;
    begin
      tmp:=a; a:=b; b:=tmp;
    end;

procedure sort(l,r:longint); inline;
    var
      i,j,mx,my,key:longint;
    begin
      i:=l; j:=r; key:=l+random(r-l+1);
      mx:=x[key]; my:=y[key];
      repeat
        while (y[i]<my) or ((y[i]=my) and (x[i]>mx)) do inc(i);
        while (y[j]>my) or ((y[j]=my) and (x[j]<mx)) do dec(j);
        if i<=j then
          begin
            swap(x[i],x[j]);
            swap(y[i],y[j]);
            inc(i); dec(j);
          end;
      until i>j;
      if i<r then sort(i,r);
      if l<j then sort(l,j);
    end;

function find(key:longint):longint; inline;
    var
      res,l,r,mid:longint;
    begin
      res:=0; l:=1; r:=d;
      while (l<=r) do
        begin
          mid:=(l+r)>>1;
          if last[mid]<key then
            begin
              res:=mid;
              l:=mid+1;
            end
          else r:=mid-1;
        end;
      exit(res);
    end;

function find1(l,r,key:longint):longint; inline;
    var
      mid,res:longint;
    begin
      res:=r;
      while (l<=r) do
        begin
          mid:=(l+r)>>1;
          if last[mid]<key then
            begin
              res:=mid;
              r:=mid-1;
            end
          else l:=mid+1;
        end;
      exit(res);
    end;

function find2(l,r,key:longint):longint; inline;
    var
      mid,res:longint;
    begin
      res:=l;
      while (l<=r) do
        begin
          mid:=(l+r)>>1;
          if ind[mid]<key then
            begin
              res:=mid;
              l:=mid+1;
            end
          else r:=mid-1;
        end;
      exit(res);
    end;

procedure solve;
    var
      i,k,u,v:longint;
    begin
      //Tinh do dai day con tang dai nhat
      d:=0;
      for i:=1 to n do
        begin
          k:=find(x[i]);
          f[i]:=k+1;
          d:=max(d,k+1);
          last[k+1]:=x[i];
          inc(sl[k+1]);
        end;
      writeln(f2,d);

      //Dem phan phoi
      for i:=2 to d do
        sl[i]:=sl[i-1]+sl[i];

      for i:=n downto 1 do
        begin
          last[sl[f[i]]]:=x[i];
          ind[sl[f[i]]]:=i;
          reg[sl[f[i]]]:=f[i];
          dec(sl[f[i]]);
        end;

      //Dem so luong
      fillchar(f,sizeof(f),0);
      f[1]:=1;
      for i:=2 to n do
      if reg[i]=1 then f[i]:=f[i-1]+1
      else
        begin
          u:=find1(sl[reg[i]-1]+1,sl[reg[i]],last[i]);
          v:=find2(sl[reg[i]-1]+1,sl[reg[i]],ind[i]);

          if reg[u-1]+2=reg[i] then f[u-1]:=0;
          if u>v then f[i]:=1
          else f[i]:=f[v]-f[u-1]; if f[i]<0 then inc(f[i],base);

          if (i<>sl[reg[i]]+1) then
            begin
                f[i]:=(f[i-1]+f[i]);
                if f[i]>base then dec(f[i],base);
            end;
        end;
      writeln(f2,f[n]);
    end;

begin
  openF;
  inp;
  sort(1,n);
  solve;
  closeF;
end.

Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(__typeof(n) i = 0; i < (n); ++i)
#define Repd(i,n) for(__typeof(n) i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(__typeof(b) i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(__typeof(a) i = (a); i >= (b); --i)
#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))
#define nl puts("")
#define sp printf(" ")
#define ok puts("ok")
//#include <conio.h>

template<class F, class T> T convert(F a, int p = -1) { stringstream ss; if (p >= 0) ss << fixed << setprecision(p); ss << a; T r; ss >> r; return r; }
template<class T> void db(T a, int p = -1) { if (p >= 0) cout << fixed << setprecision(p); cout << a << " "; }
template<class T> T gcd(T a, T b) { T r; while (b != 0) { r = a % b; a = b; b = r; } return a; }
template<class T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template<class T> T sqr(T x) { return x * x; }
template<class T> T cube(T x) { return x * x * x; }
template<class T> struct Triple { T x, y, z; Triple() {} Triple(T _x, T _y, T _z) : x(_x), y(_y), z(_z) {} };
template<class T> Triple<T> euclid(T a, T b) { if (b == 0) return Triple<T>(1, 0, a); Triple<T> r = euclid(b, a % b); return Triple<T>(r.y, r.x - a / b * r.y, r.z); }
template<class T> int getbit(T s, int i) { return (s >> i) & 1; }
template<class T> T onbit(T s, int i) { return s | (T(1) << i); }
template<class T> T offbit(T s, int i) { return s & (~(T(1) << i)); }
template<class T> int cntbit(T s) { return s == 0 ? 0 : cntbit(s >> 1) + (s & 1); }
const int bfsz = 1 << 16; char bf[bfsz + 5]; int rsz = 0;int ptr = 0;
char gc() { if (rsz <= 0) { ptr = 0; rsz = fread(bf, 1, bfsz, stdin); if (rsz <= 0) return EOF; } --rsz; return bf[ptr++]; }
void ga(char &c) { c = EOF; while (!isalpha(c)) c = gc(); }
int gs(char s[]) { int l = 0; char c = gc(); while (isspace(c)) c = gc(); while (c != EOF && !isspace(c)) { s[l++] = c; c = gc(); } s[l] = '\0'; return l; }
template<class T> bool gi(T &v) {
    v = 0; char c = gc(); while (c != EOF && c != '-' && !isdigit(c)) c = gc(); if (c == EOF) return false; bool neg = c == '-'; if (neg) c = gc();
    while (isdigit(c)) { v = v * 10 + c - '0'; c = gc(); } if (neg) v = -v; return true;
}

const double PI = 2 * acos(0);
const string months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
const int days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int dr[] = {-1, 0, +1, 0};
const int dc[] = {0, +1, 0, -1};

const int inf = (int)1e9 + 5;
const ll linf = (ll)1e16 + 5;
const double eps = 1e-9;
const ll mod = 1000000007;
typedef pair<int, int> II;
typedef Triple<int> TI;

#define maxn 300005

int n;
II f[maxn];
II A[maxn];
vector<int> V;
pair<int, II> que[maxn];

II get(int x){
    II res(0, 1);
    for(int i = x; i > 0; i -= i & -i){
        if(res.fi < f[i].fi) res = f[i];
        else if(res.fi == f[i].fi) res.se = (res.se + f[i].se) % mod;
    }
    res.fi ++;
    return res;
}

void update(int x, II P){
    for(int i = x; i < maxn; i += i & -i){
        if(f[i].fi < P.fi) f[i] = P;
        else if(f[i].fi == P.fi) f[i].se = (f[i].se + P.se) % mod;
    }
}

int main() {
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);    
    gi(n);
    Rep(i, n) { gi(A[i].fi); gi(A[i].se); V.pb(A[i].se);}  
    sort(A, A + n); sort(all(V));
    int size = 0;
    int u, v;
    II t;
    II P, res(0, 0);

    //Rep(i, n) printf("%d %d\n", A[i].fi, A[i].se);

    Rep(i, n){
        u = lower_bound(all(V), A[i].se) - V.begin() + 1;
        t = get(u - 1);
       // cout << u << " +++ " << t.fi << " ___ " << t.se << endl;
        if(t.fi > res.fi) res = t;
        else if(t.fi == res.fi) res.se = (res.se + t.se) % mod;
        que[size++] = mp(u, t);
        if(i != n - 1 && A[i + 1].fi > A[i].fi){
            Rep(run, size) update(que[run].fi, que[run].se);
            size = 0;
        }
    }
    printf("%d\n%d", res.fi, res.se);

    return 0;
}

Code mẫu của khuc_tuan

#include <iostream>
using namespace std;

const int MOD = 1000000007;

struct Data {
    int m, s;   
};

int n;
pair<int,int> a[300030];
int py[300030], F[300030], S[300030];
Data it[300030 * 4];

inline Data merge(Data a, Data b) {
    if(a.m > b.m) return a;
    else if(a.m < b.m) return b;
    else {
        a.s = (a.s + b.s) % MOD;    
        return a;
    }
}

void update(int i, int l, int r, int p, int v, int s) {
    if(l==r) {
        if(it[i].m==v) it[i].s = (it[i].s+s) % MOD;
        else if(it[i].m<v) {
            it[i].m = v;
            it[i].s = s;    
        }
        return;     
    }
    int m = (l+r) / 2;
    if(p<=m) update(2*i,l,m,p,v,s);
    if(m<p) update(2*i+1,m+1,r,p,v,s);  
    it[i] = merge(it[2*i], it[2*i+1]);
}

Data get(int i, int l, int r, int ct) {
    if(r<=ct) return it[i]; 
    int m = (l+r) / 2;
    if(m>=ct) return get(2*i,l,m,ct);
    else return merge(get(2*i,l,m,ct),get(2*i+1,m+1,r,ct));
}

int main() {
    scanf("%d", &n);
    for(int i=0;i<n;++i) {
        scanf("%d%d", &a[i].first, &a[i].second);   
        py[i] = a[i].second;
    }   
    sort(a, a+n);
    sort(py, py+n);
    for(int i=0;i<n;++i) a[i].second = lower_bound( py, py + n, a[i].second) - py;  
    for(int i=0;i<n;++i) if(i==0 || a[i].first!=a[i-1].first) {
        for(int j=i;j<n && a[j].first==a[i].first;++j) {
            Data d;
            if(a[j].second>0) d = get(1,0,n-1,a[j].second-1);
            else d.m = 0;
            F[j] = d.m + 1;
            if(F[j]==1) S[j] = 1;
            else S[j] = d.s;
        }
        for(int j=i;j<n && a[j].first==a[i].first;++j)
            update(1,0,n-1,a[j].second,F[j],S[j]);
    }
    int res = *max_element( F, F+n);
    int sum = 0;
    for(int i=0;i<n;++i) if(F[i]==res) sum = (sum + S[i]) % MOD;
    printf("%d\n%d\n", res, sum);
    return 0;
}

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