Problem p02584 (C++) — buggy submission, verdict: Time Limit Exceeded

/*
 *  TEMPLATE BY LOUIS NAVARRO
 *  FREE OF USE
 *  (inspired by other templates)
 */
#include <bits/stdc++.h>

using namespace std;

/*
 *
 * TYPE DEFINITIONS
 *
 */
// Basic types
#define uint unsigned int
#define ull unsigned long long
#define ll long long
#define ld long double
// Vectors
#define vt vector
#define vti vector<int>
#define vtl vector<long long>
#define vtd vector<double>
#define vtld vector<long double>
// Maps
#define mmap multimap
#define umap unordered_map
#define mii map<int, int>
#define mmii multimap<int, int>
#define umii unordered_map<int, int>
// Sets
#define mset multiset
#define uset unordered_set
#define umest unordered_multiset
// Array
#define ar array

/*
 *
 * FUNCTIONS / METHODS DEFINITIONS
 *
 */
#define sz(a) (int)(a).size()
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define SET(a, v) memset(a, v, sizeof(a))

/*
 *
 * LOOPS
 *
 */
#define F_OR(i, a, b, s)                                                       \\
  for (int i = (a); (s) > 0 ? i < (b) : i > (b); i += (s))
#define F_OR1(e) F_OR(i, 0, e, 1)
#define F_OR2(i, e) F_OR(i, 0, e, 1)
#define F_OR3(i, b, e) F_OR(i, b, e, 1)
#define F_OR4(i, b, e, s) F_OR(i, b, e, s)
#define GET5(a, b, c, d, e, ...) e
#define F_ORC(...) GET5(__VA_ARGS__, F_OR4, F_OR3, F_OR2, F_OR1)
#define F(...)                                                                 \\
  F_ORC(__VA_ARGS__)                                                           \\
  (__VA_ARGS__)
#define EACH(x, a) for (auto &x : a)

/*
 *
 * MATH
 *
 */

// VARIABLES
const double PI = acos(-1);
const double Pi = 3.141592653589793;

const ll MOD = 1e9 + 7;
const ll FMOD = 998244353;

// FUNCTIONS
// Binary exponentation
ll binpow(ll a, ll b) {
  ll res = 1;
  while (b > 0) {
    res *= a * (ll)(b & 1LL);
    a *= a;
    b /= 2;
  }
  return res;
}

// Binary search
template <class T, class S> int search(T a, S el, int n = 0) {
  n = n ? n : a.size();
  int i = 0;
  for (int b = n / 2; b > 0; b /= 2)
    while (i + b < n && a[i] <= el)
      i += b;
  return i;
}

// Comparisions
template <class T> bool umin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template <class T> bool umax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

// GCD / LCM
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int lcm(int a, int b) { return a * b / gcd(a, b); }
int egcd(int a, int b, int &x, int &y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  int x1, y1;
  int d = egcd(b, a % b, x1, y1);
  x = y1;
  y = x1 - y1 * (a / b);
  return d;
}

/*
 *
 * INPUT / OUTPUT
 *
 */

// Reading (input)
template <class A> void read(vt<A> &v);
template <class A, size_t S> void read(ar<A, S> &a);
template <class T> void read(T &x) { cin >> x; }
void read(double &d) {
  string t;
  read(t);
  d = stod(t);
}
void read(float &d) {
  string t;
  read(t);
  d = stod(t);
}
void read(long double &d) {
  string t;
  read(t);
  d = stold(t);
}
template <class H, class... T> void read(H &h, T &...t) {
  read(h);
  read(t...);
}
template <class A> void read(vt<A> &x) {
  EACH(a, x)
  read(a);
}
template <class A, size_t S> void read(array<A, S> &x) {
  EACH(a, x)
  read(a);
}

// Type casting (for writing)
string to_string(char c) { return string(1, c); }
string to_string(bool b) { return b ? "true" : "false"; }
string to_string(const char *s) { return string(s); }
string to_string(string s) { return s; }
string to_string(vt<bool> v) {
  string res;
  F(sz(v))
  res += char('0' + v[i]);
  return res;
}

template <size_t S> string to_string(bitset<S> b) {
  string res;
  F(S)
  res += char('0' + b[i]);
  return res;
}
template <class T> string to_string(T v) {
  bool f = 1;
  string res;
  EACH(x, v) {
    if (!f)
      res += ' ';
    f = 0;
    res += to_string(x);
  }
  return res;
}

// Writing (output)
template <class A> void write(A x) { cout << to_string(x); }
template <class H, class... T> void write(const H &h, const T &...t) {
  write(h);
  write(t...);
}
// Printing (output + "\\n")
void print() { write("\\n"); }
template <class H, class... T> void print(const H &h, const T &...t) {
  write(h);
  if (sizeof...(t))
    write(' ');
  print(t...);
}

void DBG() { cerr << "]" << endl; }
template <class H, class... T> void DBG(H h, T... t) {
  cerr << to_string(h);
  if (sizeof...(t))
    cerr << ", ";
  DBG(t...);
}

#define dbg(...)                                                               \\
  cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [",           \\
      DBG(__VA_ARGS__)

/*
 *
 * CONSTANTS
 *
 */
// const int INF = 2147483647;
const int INF = 1e9;

const ll mxN = 1e9;

/*
 *
 * CODE HERE
 *
 */
void solve() {
  ll x, k, d;
  read(x, k, d);
  x = abs(x);
  ll mn = x;
  // while (abs(x-d)<mn && k){
  // x-=d;
  //--k;
  // mn=abs(x);
  //}
  ll ch = x / d;
  if (abs(x - ch * d) >= abs(x - d - ch * d))
    ++ch;
  umin(ch, k);
  k -= ch;
  x = abs(x - ch * d);
  if (k)
    print(k & 1 ? abs(x - d) : x);
  else
    print(x);

  /*

      x, k, d
      min abs(x-d*min(a, k))

      ll ch = x/d;
      if (!x-ch*d<x-d-ch*d) ++ch;
   */
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);

  // freopen("input.txt", "r", stdin);
  // freopen("output.txt", "w", stdout);

  int t = 1;
  // read(t);
  F(t) {
    // write("Case #",  i+1, ": ");
    solve();
  }
  return 0;
}


Error: TLE

Fixed submission:

/*
 *  TEMPLATE BY LOUIS NAVARRO
 *  FREE OF USE
 *  (inspired by other templates)
 */
#include <bits/stdc++.h>

using namespace std;

/*
 *
 * TYPE DEFINITIONS
 *
 */
// Basic types
#define uint unsigned int
#define ull unsigned long long
#define ll long long
#define ld long double
// Vectors
#define vt vector
#define vti vector<int>
#define vtl vector<long long>
#define vtd vector<double>
#define vtld vector<long double>
// Maps
#define mmap multimap
#define umap unordered_map
#define mii map<int, int>
#define mmii multimap<int, int>
#define umii unordered_map<int, int>
// Sets
#define mset multiset
#define uset unordered_set
#define umest unordered_multiset
// Array
#define ar array

/*
 *
 * FUNCTIONS / METHODS DEFINITIONS
 *
 */
#define sz(a) (int)(a).size()
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define SET(a, v) memset(a, v, sizeof(a))

/*
 *
 * LOOPS
 *
 */
#define F_OR(i, a, b, s)                                                       \\
  for (int i = (a); (s) > 0 ? i < (b) : i > (b); i += (s))
#define F_OR1(e) F_OR(i, 0, e, 1)
#define F_OR2(i, e) F_OR(i, 0, e, 1)
#define F_OR3(i, b, e) F_OR(i, b, e, 1)
#define F_OR4(i, b, e, s) F_OR(i, b, e, s)
#define GET5(a, b, c, d, e, ...) e
#define F_ORC(...) GET5(__VA_ARGS__, F_OR4, F_OR3, F_OR2, F_OR1)
#define F(...)                                                                 \\
  F_ORC(__VA_ARGS__)                                                           \\
  (__VA_ARGS__)
#define EACH(x, a) for (auto &x : a)

/*
 *
 * MATH
 *
 */

// VARIABLES
const double PI = acos(-1);
const double Pi = 3.141592653589793;

const ll MOD = 1e9 + 7;
const ll FMOD = 998244353;

// FUNCTIONS
// Binary exponentation
ll binpow(ll a, ll b) {
  ll res = 1;
  while (b > 0) {
    res *= a * (ll)(b & 1LL);
    a *= a;
    b /= 2;
  }
  return res;
}

// Binary search
template <class T, class S> int search(T a, S el, int n = 0) {
  n = n ? n : a.size();
  int i = 0;
  for (int b = n / 2; b > 0; b /= 2)
    while (i + b < n && a[i] <= el)
      i += b;
  return i;
}

// Comparisions
template <class T> bool umin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template <class T> bool umax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

// GCD / LCM
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int lcm(int a, int b) { return a * b / gcd(a, b); }
int egcd(int a, int b, int &x, int &y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  int x1, y1;
  int d = egcd(b, a % b, x1, y1);
  x = y1;
  y = x1 - y1 * (a / b);
  return d;
}

/*
 *
 * INPUT / OUTPUT
 *
 */

// Reading (input)
template <class A> void read(vt<A> &v);
template <class A, size_t S> void read(ar<A, S> &a);
template <class T> void read(T &x) { cin >> x; }
void read(double &d) {
  string t;
  read(t);
  d = stod(t);
}
void read(float &d) {
  string t;
  read(t);
  d = stod(t);
}
void read(long double &d) {
  string t;
  read(t);
  d = stold(t);
}
template <class H, class... T> void read(H &h, T &...t) {
  read(h);
  read(t...);
}
template <class A> void read(vt<A> &x) {
  EACH(a, x)
  read(a);
}
template <class A, size_t S> void read(array<A, S> &x) {
  EACH(a, x)
  read(a);
}

// Type casting (for writing)
string to_string(char c) { return string(1, c); }
string to_string(bool b) { return b ? "true" : "false"; }
string to_string(const char *s) { return string(s); }
string to_string(string s) { return s; }
string to_string(vt<bool> v) {
  string res;
  F(sz(v))
  res += char('0' + v[i]);
  return res;
}

template <size_t S> string to_string(bitset<S> b) {
  string res;
  F(S)
  res += char('0' + b[i]);
  return res;
}
template <class T> string to_string(T v) {
  bool f = 1;
  string res;
  EACH(x, v) {
    if (!f)
      res += ' ';
    f = 0;
    res += to_string(x);
  }
  return res;
}

// Writing (output)
template <class A> void write(A x) { cout << to_string(x); }
template <class H, class... T> void write(const H &h, const T &...t) {
  write(h);
  write(t...);
}
// Printing (output + "\\n")
void print() { write("\\n"); }
template <class H, class... T> void print(const H &h, const T &...t) {
  write(h);
  if (sizeof...(t))
    write(' ');
  print(t...);
}

void DBG() { cerr << "]" << endl; }
template <class H, class... T> void DBG(H h, T... t) {
  cerr << to_string(h);
  if (sizeof...(t))
    cerr << ", ";
  DBG(t...);
}

#define dbg(...)                                                               \\
  cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [",           \\
      DBG(__VA_ARGS__)

/*
 *
 * CONSTANTS
 *
 */
// const int INF = 2147483647;
const int INF = 1e9;

const ll mxN = 1e9;

/*
 *
 * CODE HERE
 *
 */
void solve() {
  ll x, k, d;
  read(x, k, d);
  x = abs(x);
  ll mn = x;
  while (abs(x - d) < mn && k) {
    x -= d;
    --k;
    mn = abs(x);
  }
  x = abs(x);
  if (k)
    print(k & 1 ? abs(x - d) : x);
  else
    print(x);
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);

  // freopen("input.txt", "r", stdin);
  // freopen("output.txt", "w", stdout);

  int t = 1;
  // read(t);
  F(t) {
    // write("Case #",  i+1, ": ");
    solve();
  }
  return 0;
}