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

#include <algorithm>
#include <cassert>
#include <cmath>
#include <functional>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <vector>
// #include<bits/stdc++.h>
#define rep(i, x) for (ll i = 0; i < x; i++)
#define rep2(i, x) for (ll i = 1; i <= x; i++)
#define all(a) (a).begin(), (a).end()
using ll = long long;
using ld = long double;
using namespace std;
const ll INF = 1000000000000000000;
const ll mod = 1000000007;
const ld pi = 3.141592653589793238;

/*bool IsPrime(ll num) {
        if (num < 2) return false;
        else if (num == 2) return true;
        else if (num % 2 == 0) return false; // 偶数はあらかじめ除く
        double sqrtNum = sqrt(num);
        for (int i = 3; i <= sqrtNum; i += 2) {
                if (num % i == 0) { // 素数ではない
                        return false;
                }
        }
        // 素数である
        return true;
}*/
/*ll gcd(ll a, ll b) {
        if (a < b)swap(a, b);
        if (a % b == 0)return b;
        return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
        return a / gcd(a, b) * b;
}*/
/*ll keta(ll n) {
        ll res = 0;
        while (n >= 1) {
                res += n % 10; n /= 10;
        }
        return res;
}*/
/*ll modpow(ll x, ll y) {
        ll res = 1;
        while (y) {
                if (y % 2) { res *= x; res %= mod; }
                x = x * x % mod; y /= 2;
        }
        return res;
}*/
/*ll nCk(ll n, ll k) {
        ll a = 1, b = 1;
        for (int h = n - k + 1; h <= n; h++) { a *= h; a %= mod; }
        for (int h = 1; h <= k; h++) { b *= h; b %= mod; }
        return a * modpow(b, mod - 2) % mod;
}*/
// printf("%.10f\\n", n);

ll test[12345678];
signed main() {
  string s, t;
  ll n, m, a, b, cnt = 0, ans = 0;
  ll x, k, d;
  cin >> x >> k >> d;
  x = abs(x);
  ld aa = x / k;
  if (aa >= d) {
    cout << x - (k * d) << endl;
    return 0;
  }
  k -= (x / d);
  x %= d;
  cnt = abs(x - d);
  ans = x;
  if (k % 2 == 0) {
    cout << ans << endl;
  } else {
    cout << cnt << endl;
  }
  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <cassert>
#include <cmath>
#include <functional>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <vector>
// #include<bits/stdc++.h>
#define rep(i, x) for (ll i = 0; i < x; i++)
#define rep2(i, x) for (ll i = 1; i <= x; i++)
#define all(a) (a).begin(), (a).end()
using ll = long long;
using ld = long double;
using namespace std;
const ll INF = 1000000000000000000;
const ll mod = 1000000007;
const ld pi = 3.141592653589793238;

/*bool IsPrime(ll num) {
        if (num < 2) return false;
        else if (num == 2) return true;
        else if (num % 2 == 0) return false; // 偶数はあらかじめ除く
        double sqrtNum = sqrt(num);
        for (int i = 3; i <= sqrtNum; i += 2) {
                if (num % i == 0) { // 素数ではない
                        return false;
                }
        }
        // 素数である
        return true;
}*/
/*ll gcd(ll a, ll b) {
        if (a < b)swap(a, b);
        if (a % b == 0)return b;
        return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
        return a / gcd(a, b) * b;
}*/
/*ll keta(ll n) {
        ll res = 0;
        while (n >= 1) {
                res += n % 10; n /= 10;
        }
        return res;
}*/
/*ll modpow(ll x, ll y) {
        ll res = 1;
        while (y) {
                if (y % 2) { res *= x; res %= mod; }
                x = x * x % mod; y /= 2;
        }
        return res;
}*/
/*ll nCk(ll n, ll k) {
        ll a = 1, b = 1;
        for (int h = n - k + 1; h <= n; h++) { a *= h; a %= mod; }
        for (int h = 1; h <= k; h++) { b *= h; b %= mod; }
        return a * modpow(b, mod - 2) % mod;
}*/
// printf("%.10f\\n", n);

ll test[12345678];
signed main() {
  string s, t;
  ll n, m, a, b, cnt = 0, ans = 0;
  ll x, k, d;
  cin >> x >> k >> d;
  rep(i, k) {
    if (x >= 0) {
      x -= d;
    } else {
      x += d;
    }
  }
  cout << abs(x) << endl;
  return 0;
}