Problem p02775 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << "\n"
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES\n" : "NO\n")
#define Yes(n) cout << ((n) ? "Yes\n" : "No\n")
#define mp make_pair
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef tuple<ll, ll, ll> tll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
int main() {
  string s;
  cin >> s;
  ll n = sz(s);
  vvll dp(n + 1, vll(2, INF));
  dp[0][0] = 0;
  reverse(all(s));
  rep(i, n + 1) rep(j, 2) {
    if (dp[i][j] == INF)
      continue;
    ll c = s[i] - '0';
    ll no = 10 - c;
    if (j == 0) {
      chmin(dp[i + 1][0], dp[i][j] + c);
      chmin(dp[i + 1][1], dp[i][j] + no);
    } else {
      chmin(dp[i + 1][0], dp[i][j] + 1 + c);
      chmin(dp[i + 1][1], dp[i][j] + no - 1);
    }
  }
  COUT(min(dp[n][0], dp[n][1] + 1LL));
}

Fixed submission:
#include <algorithm>
#include <bits/stdc++.h>
#include <cmath>
#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORR(i, a, b) for (ll i = (a); i <= (b); i++)
#define repR(i, n) for (ll i = n; i >= 0; i--)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout << (x) << "\n"
#define PQ priority_queue<ll>
#define PQR priority_queue<ll, vector<ll>, greater<ll>>
#define YES(n) cout << ((n) ? "YES\n" : "NO\n")
#define Yes(n) cout << ((n) ? "Yes\n" : "No\n")
#define mp make_pair
#define sz(x) (ll)(x).size()
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef tuple<ll, ll, ll> tll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using vc = vector<char>;
using vvc = vector<vc>;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll dx[4] = {0, 1, 0, -1};
ll dy[4] = {1, 0, -1, 0};
int main() {
  string s;
  cin >> s;
  ll n = sz(s);
  vvll dp(n + 1, vll(2, INF));
  dp[0][0] = 0;
  reverse(all(s));
  rep(i, n) rep(j, 2) {
    if (dp[i][j] == INF)
      continue;
    ll c = s[i] - '0';
    ll no = 10 - c;
    if (j == 0) {
      chmin(dp[i + 1][0], dp[i][j] + c);
      chmin(dp[i + 1][1], dp[i][j] + no);
    } else {
      chmin(dp[i + 1][0], dp[i][j] + 1 + c);
      chmin(dp[i + 1][1], dp[i][j] + no - 1);
    }
  }
  COUT(min(dp[n][0], dp[n][1] + 1LL));
}