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

#include <iostream>
#include <algorithm>
using namespace std;

long long calcVND(long long u)
{
    if (u <= 100) return u * 200;
    if (u <= 10000) return calcVND(100) + (u - 100) * 300;
    if (u <= 1000000) return calcVND(10000) + (u - 10000) * 500;
    return calcVND(1000000) + (u - 1000000) * 700;
}

long long calcKWh(long long u)
{
    if (calcVND(100) >= u) return u / 200;
    if (calcVND(10000) >= u) return 100 + (u - calcVND(100)) / 300;
    if (calcVND(1000000) >= u) return 10000 + (u - calcVND(10000)) / 500;
    return 1000000 + (u - calcVND(1000000)) / 700;
}

int main()
{
    long long x, y;
    cin >> x >> y;

    long long total = calcKWh(x), low = 0, high = total / 2, ans = -1;
    while (low <= high)
    {
        long long mid = (low + high) / 2;
        long long dif = calcVND(total - mid) - calcVND(mid);
        if (dif == y)
        {
            ans = mid; break;
        }
        if (dif < y) high = mid - 1;
        else low = mid + 1;
    }

    cout << calcVND(ans) << endl;
}

Code mẫu của happyboy99x

#include <cstdio>
typedef long long LL;

LL x, y;

int moneyTokWh(int money) {
    int res = 0;
    if( money > 497990000 ) {
        res += (money - 497990000)/700;
        money = 497990000;
    }
    if( money > 2990000 ) {
        res += (money - 2990000)/500;
        money = 2990000;
    }
    if( money > 20000 ) {
        res += (money - 20000)/300;
        money = 20000;
    }
    res += money/200;
    return res;
}

LL kWhToMoney( int kwh ) {
    if(kwh <= 100) return (LL) kwh * 200;
    if(kwh <= 10000) return (LL) 20000 + (kwh-100)*300;
    if(kwh <= 1000000) return (LL) 2990000 + (kwh-10000)*500;
    return (LL) 497990000 + (kwh-1000000)*700;
}

int main() {
    scanf("%lld%lld",&x,&y);
    x = moneyTokWh(x);
    int L = 0, H = x;
    while(L <= H) {
        int mid = (L+H)/2;
        int a = kWhToMoney(x-mid) - kWhToMoney(mid);
        if( a == y ) {
            printf("%lld\n",kWhToMoney(mid));
            return 0;
        }
        if( a < y ) H = mid-1;
        else L = mid+1;
    }
    return 0;
}

Code mẫu của ladpro98

program bill;
uses    math;
type    e=record
        val:int64;
        full:boolean;
        end;
const   fi='';
        lim:array[1..3] of longint = (100,10000,1000000);
        limP:array[1..3] of longint = (20000,2970000,495000000);
        p:array[1..4] of longint = (200,300,500,700);
var     x,y:int64;
        inp:text;

function KwhToMoney(a:int64):int64;
var     s:int64;
begin
        if a<=lim[1] then exit(p[1]*a);
        s:=lim[1]*p[1];
        dec(a,lim[1]);
        if a<=(lim[2]-lim[1]) then exit(s+p[2]*a);
        inc(s,(lim[2]-lim[1])*p[2]);
        dec(a,lim[2]-lim[1]);
        if a<=(lim[3]-lim[2]) then exit(s+p[3]*a);
        inc(s,(lim[3]-lim[2])*p[3]);
        dec(a,(lim[3]-lim[2]));
        exit(s+p[4]*a);
end;

function MoneyToKwh(a:int64):e;
var     s:int64;
        tp:e;
begin
        if a<=limP[1] then
        begin
                if a mod p[1]=0 then tp.full:=true
                else tp.full:=false;
                tp.val:=a div p[1];
                exit(tp);
        end;
        s:=lim[1];
        dec(a,limP[1]);
        if a<=limP[2] then
        begin
                if a mod p[2]=0 then tp.full:=true
                else tp.full:=false;
                tp.val:=s+a div p[2];
                exit(tp);
        end;
        s:=lim[2];
        dec(a,limP[2]);
        if a<=limP[3] then
        begin
                if a mod p[3]=0 then tp.full:=true
                else tp.full:=false;
                tp.val:=s+a div p[3];
                exit(tp);
        end;

        s:=lim[3];
        dec(a,limP[3]);
        if a mod p[4]=0 then tp.full:=true
                else tp.full:=false;
                tp.val:=s+a div p[4];
                exit(tp);
end;

procedure process;
var     l,r,t,m:int64;
        a,b:e;
begin
        l:=0;r:=x;
        while (l<=r) do
        begin
                m:=(l+r) div 2;
                a:=MoneyToKwh(m);
                b:=MoneyToKwh(m+y);
                t:=KwhToMoney(a.val+b.val);
                if t=x then
                if a.full and b.full then
                begin
                        write(m);
                        exit;
                end
                else    r:=m-1;
                if t<x then l:=m+1
                else    r:=m-1;
        end;
end;

begin
        assign(inp,fi);reset(inp);
        readln(inp,x,y);
        process;

end.

Code mẫu của RR

#include <sstream>
#include <iomanip>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <string>
#include <deque>
#include <complex>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define FORN(i,a,b) for(int i=(a),_b=(b);i<_b;i++)
#define DOWN(i,a,b) for(int i=a,_b=(b);i>=_b;i--)
#define SET(a,v) memset(a,v,sizeof(a))
#define sqr(x) ((x)*(x))
#define ll long long
#define F first
#define S second
#define PB push_back
#define MP make_pair

#define DEBUG(x) cout << #x << " = "; cout << x << endl;
#define PR(a,n) cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl;
#define PR0(a,n) cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl;
using namespace std;

//Buffer reading
int INP,AM,REACHEOF;
#define BUFSIZE (1<<12)
char BUF[BUFSIZE+1], *inp=BUF;
#define GETCHAR(INP) { \
    if(!*inp) { \
        if (REACHEOF) return 0;\
        memset(BUF,0,sizeof BUF);\
        int inpzzz = fread(BUF,1,BUFSIZE,stdin);\
        if (inpzzz != BUFSIZE) REACHEOF = true;\
        inp=BUF; \
    } \
    INP=*inp++; \
}
#define DIG(a) (((a)>='0')&&((a)<='9'))
#define GN(j) { \
    AM=0;\
    GETCHAR(INP); while(!DIG(INP) && INP!='-') GETCHAR(INP);\
    if (INP=='-') {AM=1;GETCHAR(INP);} \
    j=INP-'0'; GETCHAR(INP); \
    while(DIG(INP)){j=10*j+(INP-'0');GETCHAR(INP);} \
    if (AM) j=-j;\
}
//End of buffer reading

const long double PI = acos((long double) -1.0);

long long conv(long long x) {
    long long res = 0;
    res += min(x, 100LL) * 200;
    x -= 100;
    if (x <= 0) return res;

    res += min(x, 10000LL - 100) * 300;
    x -= 10000 - 100;
    if (x <= 0) return res;

    res += min(x, 1000000LL - 10000) * 500;
    x -= 1000000 - 10000;
    if (x <= 0) return res;

    res += x * 700;
    return res;
}

long long rev(long long x) {
    long long res = 0;
    if (x <= 100 * 200) return x / 200;
    res += 100;
    x -= 100 * 200;

    if (x <= (10000 - 100) * 300) return res + x / 300;
    res = 10000;
    x -= (10000 - 100) * 300;

    if (x <= (1000000 - 10000) * 500) return res + x / 500;
    res = 1000000;
    x -= (1000000 - 10000) * 500;

    return x / 700 + res;
}

int main() {
    long long x, y;
    while (cin >> x >> y) {
        long long sum = rev(x);

        FOR(i,1,sum/2) {
            long long a = conv(i);
            long long b = conv(sum-i);

            if (b-a == y) {
                cout << a << endl;
                break;
            }
        }
    }
    return 0;
}

Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>

#include <ctime>
#include <deque>
#include <bitset>
#include <cctype>
#include <utility>
#include <cassert>

using namespace std;

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

#define Rep(i,n) for(int i = 0; i < (n); ++i)
#define Repd(i,n) for(int i = (n)-1; i >= 0; --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 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))

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> 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> 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 = (int) 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;
}

typedef pair<int, int> II;

const ld PI = acos(-1.0);
const ld eps = 1e-9;

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 ll mod = (ll)1e9 + 7;

ll X, Y, sum;
ll f[10];
ll a[] = {100, 10000, 1000000};

ll cal(ll X){
    ll res = 0;
    if(X > f[2]){
        res = (X - f[2]) / 700 + 1000000;
    }
    else if(X > f[1]){
        res = (X - f[1]) / 500 + 10000;
    }
    else if(X > f[0]){
        res = (X - f[0]) / 300 + 100;
    }
    else res = X / 200;
    return res;
}

ll tinh(ll X){
    ll res = 0;
    if(X > a[2]){
        res = (X - a[2]) * 700 + f[2];
    }
    else if(X > a[1]){
        res = (X - a[1]) * 500 + f[1];
    }
    else if(X > a[0]){
        res = (X - a[0]) * 300 + f[0];
    }
    else res = X * 200;
    return res;
}

int  main()
{
//  freopen("in.txt", "r", stdin);

    cin >> X >> Y;
    f[0] = 100 * 200;
    f[1] = 9900 * 300 + f[0];
    f[2] = 990000 * 500 + f[1];

    sum = cal(X);
    ll ret, ret1;
    For(i, 1, 1000000){
        ret = tinh(i);
        ret1 = tinh(sum - i);
        if(ret1 - ret == Y){
            cout << ret;
            return 0;
        }
    }

    ll d = Y / 700;
    cout << tinh((sum - d) / 2);

    return 0;
}

Code mẫu của skyvn97

#include<stdio.h>
typedef unsigned long long ull;
ull x,y,l,m,r,a,b;
ull cost(ull a)
{
    if (a<=100) return (200*a);
    if (a<=10000) return (300*a-10000);
    if (a<=1000000) return (500*a-2010000);
    return (700*a-202010000);
}
int main(void)
{
    scanf("%llu",&x);
    scanf("%llu",&y);
    l=0;
    r=x;
    while (true)
          {
           if (l==r)              
              {
               if (cost(l)==x) {a=l;break;}
              }
           if (r-l==1)
              {
               if (cost(l)==x) {a=l; break;}
               if (cost(r)==x) {a=r; break;}
              }
           m=(l+r)/2;
           if (cost(m)==x)
              {
               a=m;
               break;
              }
           if (cost(m)>x) r=m-1;
           if (cost(m)<x) l=m+1;              
          }
    l=0;
    r=a/2;
    while (true)
          {
           if (l==r)
              {
               if (cost(a-l)-cost(l)==y) {b=l;break;}
              }
           if (r-l==1)
              {
               if (cost(a-l)-cost(l)==y) {b=l;break;}
               if (cost(a-r)-cost(r)==y) {b=r;break;}
              }
           m=(l+r)/2;
           if (cost(a-m)-cost(m)==y)
              {
               b=m;
               break;
              }
           if (cost(a-m)-cost(m)>y) l=m+1;
           if (cost(a-m)-cost(m)<y) r=m-1;
          }
    printf("%llu",cost(b));
}