Hướng dẫn giải của Xe buýt


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=100010;
type ar=array[0..maxn] of longint;
var n,xx,yy,mx:longint;
    a,b,c,y,d:ar;
    col:array[0..maxn] of int64;
    re:int64;

procedure rf;
var i:longint;
begin
     read(xx,yy,n);
     for i:=1 to n do
     begin
          read(a[i],b[i],c[i]);
          y[i]:=b[i]; d[i]:=i;
     end;
end;

procedure sort(l,r:longint);
var i,j,x,t:longint;
begin
     i:=l; j:=r; x:=y[(i+j) shr 1];
     repeat
           while y[i]<x do i:=i+1;
           while y[j]>x do j:=j-1;
           if i<=j then
           begin
                t:=y[i]; y[i]:=y[j]; y[j]:=t;
                t:=d[i]; d[i]:=d[j]; d[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 discr;
var i:longint;
begin
     sort(1,n);
     mx:=1; b[d[1]]:=1;
     for i:=2 to n do
     begin
          if y[i]>y[mx] then
          begin
               inc(mx);
               y[mx]:=y[i];
          end;
          b[d[i]]:=mx;
     end;
end;

procedure sortt(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;
                t:=c[i]; c[i]:=c[j]; c[j]:=t;
                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 update(x:longint;val:int64);
begin
     while x<=mx do
     begin
          if val<=col[x] then exit;
          col[x]:=val;
          x:=x+x and (-x);
     end;
end;

function get(x:longint):int64;
var r:int64;
begin
     r:=0;
     while x>0 do
     begin
          r:=max(r,col[x]);
          x:=x-x and (-x);
     end;
     exit(r);
end;

procedure pr;
var i:longint; row,x:int64;
begin
     re:=0; row:=0; i:=1;
     while (a[i]<1) or ((a[i]=1) and (b[i]<1)) do i:=i+1;
     while i<=n do
     begin
          if (i=1) or (a[i]<>a[i-1]) then row:=0;
          x:=get(b[i]);
          row:=max(row,x)+c[i];
          update(b[i],row);
          re:=max(re,row);
          inc(i);
     end;
     writeln(re);
end;

begin
     assign(input,fi); reset(input);
     rf;
     discr;
     sortt(1,n);
     pr;
     close(input);
end.

Code mẫu của ladpro98

program MBUS;
uses    math;
const   maxn=100005;
        fi='';
type    e=record
                x,z,dy:longint;
        end;
        e2=record
                v,p:longint;
        end;
var     a:array[1..maxn] of e;
        col:array[0..maxn] of e2;
        bit:array[1..maxn] of int64;
        x,y,n,d:longint;
        res:int64;

procedure input;
var     inp:text;
        i:longint;
begin
        assign(inp,fi);reset(inp);
        readln(inp,x,y,n);
        for i:=1 to n do begin
                readln(inp,a[i].x,col[i].v,a[i].z);
                col[i].p:=i;
        end;
        close(inp);
end;

procedure sortA(l,r:longint);
var     i,j:longint;
        p,t:e;
begin
        if l>=r then exit;
        i:=l;j:=r;
        p:=a[random(r-l+1)+l];
        repeat
                while (a[i].x<p.x) or ((a[i].x=p.x) and (a[i].dy<p.dy)) do inc(i);
                while (a[j].x>p.x) or ((a[j].x=p.x) and (a[j].dy>p.dy)) do dec(j);
                if i<=j then begin
                        if i<j then begin
                                t:=a[i];
                                a[i]:=a[j];
                                a[j]:=t
                        end;
                        inc(i);dec(j);
                end;
        until i>j;
        sortA(l,j);sortA(i,r);
end;

procedure sortCol(l,r:longint);
var     i,j:longint;
        p,t:e2;
begin
        if l>=r then exit;
        i:=l;j:=r;
        p:=col[random(r-l+1)+l];
        repeat
                while (col[i].v<p.v) do inc(i);
                while (col[j].v>p.v) do dec(j);
                if i<=j then begin
                        if i<j then begin
                                t:=col[i];
                                col[i]:=col[j];
                                col[j]:=t;
                        end;
                        inc(i);dec(j);
                end;
        until i>j;
        sortCol(l,j);sortCol(i,r);
end;

procedure discrete;
var     i:longint;
begin
        sortCol(1,n);
        col[0].v:=-1;
        for i:=1 to n do begin
                if col[i].v<>col[i-1].v then inc(d);
                a[col[i].p].dy:=d;
        end;
end;

procedure update(i,v:longint);
begin
        while i<=d do begin
                bit[i]:=max(bit[i],v);
                i:=i+i and (-i);
        end;
end;

function get(i:longint):longint;
var     t:longint;
begin
        t:=0;
        while i>0 do begin
                t:=max(t,bit[i]);
                i:=i-i and (-i);
        end;
        exit(t);
end;

procedure dp;
var     i:longint;
        t:int64;
begin
        sortA(1,n);
        for i:=1 to n do begin
                t:=get(a[i].dy)+a[i].z;
                if bit[a[i].dy]<t then
                update(a[i].dy,t);
                res:=max(res,t);
        end;
end;

begin
        input;
        discrete;
        dp;
        write(res);
end.

Code mẫu của RR

#include <iostream>
#include <algorithm>
#include <map>
#define MAXN 100111
#define F first
#define S second
#define _(u) (u&(-u))
#define FOR(i,a,b) for(long i=a; i<=b; i++)
#define FORV(i,v)  for(typeof(v.begin()) i=v.begin(); i!=v.end(); i++)
using namespace std;

long n,X,Y,bit[MAXN],f[MAXN];
pair<pair<long,long>,long> a[MAXN];
map<long,long> m;

void inp() {
    scanf("%ld %ld %ld",&X,&Y,&n);
    FOR(i,1,n) {
        scanf("%ld %ld %ld",&a[i].F.F,&a[i].F.S,&a[i].S);
        if (a[i].F.F<1 || a[i].F.S<1) a[i].S=0;
    }

    m[1]=1; m[Y]=0;
    FOR(i,1,n) m[a[i].F.S]=0;
    FORV(i,m) {
        typeof(i) j=i; j--;
        i->second=j->second+1;
    }

    FOR(i,1,n) a[i].F.S=m[a[i].F.S];
    Y=m[Y];

    sort(a+1,a+n+1);
}

long get(long u) {
    if (u<=0) return 0;
    long v=u-_(u);
    return max(bit[u],get(v));
}

void update(long k,long u) {
    bit[u]=max(bit[u],k);
    long v=u+_(u);
    if (v<=n+1) update(k,v);
}

void solve() {
    long res=0;
    FOR(i,1,n) {
        f[i]=get(a[i].F.S)+a[i].S;
        update(f[i],a[i].F.S);
        res=max(res,f[i]);
    }
    printf("%ld",res);
}

int main() {
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    inp();
    solve();
    return 0;
}

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[] = {0, +1, 0, -1};
const int dc[] = {+1, 0, -1, 0};
const int inf = (int)1e9 + 5;
const ll linf = (ll)1e16 + 5;
const double eps = 1e-9;
const ll mod = 100000007;
typedef pair<int, int> II;

#define maxn 100005
#define maxe 100005

ll f[maxn];
vector<int> vx, vy;
pair<II, II> P[maxn];

int X, Y, n;

void update(int u, ll x){
    for(int i = u; i < maxn; i += i & -i){
        f[i] = max(f[i], x);
    }
}

ll get(int u){
    ll res = 0;
    for(int i = u; i > 0; i -= i & -i){
        res = max(res, f[i]);
    }
    return res;
}

int main() {
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
    gi(X); gi(Y); gi(n);
    vx.resize(n + 2); vy.resize(n + 2);
    ms(f, 0);
    vx[0] = (X); vy[0] = (Y); vx[1] = (1); vy[1] = (1);
    int x, y;
    ll c, t;

    Rep(i, n){
        gi(P[i].fi.fi); gi(P[i].fi.se); gi(P[i].se.fi);
        vx[i + 2] = (P[i].fi.fi); vy[i + 2] = (P[i].fi.se);
    }
    P[n] = mp(mp(1, 1), mp(0, 0));
    P[n + 1] = mp(mp(X, Y), mp(0, 0)); 

    sort(all(vx)); sort(all(vy)); sort(P, P + n + 2);
    ll res;
    For(i, 1, n + 1){
        y = lower_bound(all(vy), P[i].fi.se) - vy.begin() + 1;
        t = get(y);
        update(y, t + P[i].se.fi);
        if(i == n + 1) res = t + P[i].se.fi;
    }

    cout << res;
    return 0;
}

Code mẫu của ll931110

#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <iostream>
#include <map>
#include <set>
#include <sstream>
#include <stack>
#include <queue>
#include <vector>
#include <utility>
using namespace std;

int x[100010],y[100010],c[100010],tx[100010];
vector< pair<int,int> > a;
vector< pair<int,int> > v[100010];
int n,m,k;

void update(int p,int q)
{
    while (p <= 100000)
    {
        tx[p] = max(tx[p],q);  p += (p & -p);
    };
};

int calc(int p)
{
    int q = 0;
    while (p)
    {
        q = max(q,tx[p]);  p -= (p & -p);
    };
    return q;
};

int main()
{
//    freopen("bus.in","r",stdin);
//    freopen("bus.ou","w",stdout);
    scanf("%d%d%d", &n, &m, &k);
    for (int i = 1; i <= k; i++) 
      scanf("%d%d%d", &x[i], &y[i], &c[i]);

    for (int i = 1; i <= k; i++)
      a.push_back(make_pair(x[i],i));
    sort(a.begin(),a.end());
    x[a[0].second] = 1;  int cc = 1;
    for (int i = 1; i < a.size(); i++) 
    {
        if (a[i].first > a[i - 1].first) cc++;
        x[a[i].second] = cc;
    };

    a.clear();
    for (int i = 1; i <= k; i++)
      a.push_back(make_pair(y[i],i));
    sort(a.begin(),a.end());
    y[a[0].second] = 1;  cc = 1;
    for (int i = 1; i < a.size(); i++) 
    {
        if (a[i].first > a[i - 1].first) cc++;
        y[a[i].second] = cc;
    };

    for (int i = 1; i <= k; i++) v[x[i]].push_back(make_pair(y[i],i));
    for (int i = 1; i <= 100000; i++) sort(v[i].begin(),v[i].end());
    int ret = 0;
    memset(tx,0,sizeof(tx));
    for (int i = 1; i <= 100000; i++)
      for (int j = 0; j < v[i].size(); j++)
      {
            int u = v[i][j].first;  int pos = v[i][j].second;
//            cout << i << ' ' << u << ' ' << pos << endl;
            int tmp = calc(u);
            ret = max(ret,tmp + c[pos]);
            update(u,tmp + c[pos]);            
        };
    printf("%d\n", ret);
};

Code mẫu của khuc_tuan

#include <iostream>
#include <cstdio>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;

#define Rep(i,n) for(int i=0;i<(n);++i)
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Ford(i,a,b) for(int i=(a);i>=(b);--i)
#define fi first
#define se second
#define pb push_back
#define MP make_pair

const int maxn=100010;

struct Data{
    int x,y,z;
};

int cmp(Data a,Data b){
    if(a.x==b.x)return a.y<b.y;
    else return a.x<b.x;
}

int X,Y,n,nt;
int T[maxn];
Data a[maxn];
long long F[maxn];
long long B[maxn];

int main() {
    scanf("%d%d%d",&X,&Y,&n);
    Rep(i,n)scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].z);
    a[n].x=X,a[n].y=Y,a[n].z=0;
    ++n;
    Rep(i,n)T[i]=a[i].y;
    sort(T,T+n);
    nt=unique(T,T+n)-T;
    sort(a,a+n,cmp);
    Rep(i,n){
        int id=lower_bound(T,T+nt,a[i].y)-T+1;
        int id2=id;
        long long r=0;
        for(;id>0;id&=(id-1))r=max(r,B[id]);
        r+=a[i].z;
        F[i]=r;
        for(;id2<=nt;id2+=id2&(-id2))B[id2]=max(B[id2],r);
    }
    Ford(i,n-1,0)if(a[i].x==X&&a[i].y==Y){cout<<F[i]<<endl;break;}
    return 0;   
}

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