Problem p03570 (C++)

Buggy submission (status: Memory Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define Ans(f, y, n)                                                           \
  if (f)                                                                       \
    cout << y << endl;                                                         \
  else                                                                         \
    cout << n << endl;
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \
  cout << #v << "=" << endl;                                                   \
  REP(i, v.size()) { cout << v[i] << ","; }                                    \
  cout << endl;
#define mdebug(m)                                                              \
  cout << #m << "=" << endl;                                                   \
  REP(i, m.size()) {                                                           \
    REP(j, m[i].size()) { cout << m[i][j] << ","; }                            \
    cout << endl;                                                              \
  }
#define pb push_back
#define int long long
#define INF 1000000000000000000

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

template <typename T> void readv(vector<T> &a) { REP(i, a.size()) cin >> a[i]; }
void readv_m1(vector<int> &a) {
  REP(i, a.size()) {
    cin >> a[i];
    a[i]--;
  }
}

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};

int mod = 1000000007;
// int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod
#define AddMult(x, y, z) x = (x + (y) * (z)) % mod

signed main() {

  string s;
  cin >> s;
  int n = SZ(s);
  vec dp(bit(26), INF);
  dp[0] = 0;
  int tmp = 0;
  REP(i, n) {
    tmp ^= bit(s[i] - 'a');
    int m = INF;
    REP(k, 26) Min(m, dp[tmp ^ bit(k)]);
    if (m < dp[tmp])
      dp[tmp] = m + 1;
    else if (i == n - 1)
      dp[tmp]++;
  }

  cout << dp[tmp] << endl;

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define Ans(f, y, n)                                                           \
  if (f)                                                                       \
    cout << y << endl;                                                         \
  else                                                                         \
    cout << n << endl;
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \
  cout << #v << "=" << endl;                                                   \
  REP(i, v.size()) { cout << v[i] << ","; }                                    \
  cout << endl;
#define mdebug(m)                                                              \
  cout << #m << "=" << endl;                                                   \
  REP(i, m.size()) {                                                           \
    REP(j, m[i].size()) { cout << m[i][j] << ","; }                            \
    cout << endl;                                                              \
  }
#define pb push_back
// #define int long long
#define INF 1000000000

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

template <typename T> void readv(vector<T> &a) { REP(i, a.size()) cin >> a[i]; }
void readv_m1(vector<int> &a) {
  REP(i, a.size()) {
    cin >> a[i];
    a[i]--;
  }
}

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};

int mod = 1000000007;
// int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod
#define AddMult(x, y, z) x = (x + (y) * (z)) % mod

signed main() {

  string s;
  cin >> s;
  int n = SZ(s);
  vec dp(bit(26), INF);
  dp[0] = 0;
  int tmp = 0;
  REP(i, n) {
    tmp ^= bit(s[i] - 'a');
    int m = INF;
    REP(k, 26) Min(m, dp[tmp ^ bit(k)]);
    if (m < dp[tmp])
      dp[tmp] = m + 1;
    else if (i == n - 1)
      dp[tmp]++;
  }

  cout << dp[tmp] << endl;

  return 0;
}