Problem p03074 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <array>
#include <assert.h>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits.h>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
// #define MOD 998244353
#define MEM_SIZE 10000
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template <typename T> void DEBUG(T e) {
  if (DEBUG_OUT == false)
    return;
  std::cout << e << " ";
}
template <typename T> void DEBUG(const std::vector<T> &v) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void DEBUG(const std::vector<std::vector<T>> &vv) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &v : vv) {
    DEBUG(v);
  }
}
template <class T, class... Ts> void DEBUG(T d, Ts... e) {
  if (DEBUG_OUT == false)
    return;
  DEBUG(d);
  DEBUG(e...);
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    abort();
  }
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

void solve(void) {

  int N, K;
  cin >> N;
  cin >> K;
  vector<pair<int, int>> vp;
  vp.emplace_back(-1, 0);
  for (int i = 0; i < N; i++) {
    char X;
    cin >> X;

    int x = X - '0';
    if (vp.empty() || vp.back().first != x) {
      vp.push_back(make_pair(x, 1));
    } else {
      vp.back().second++;
    }
  }

  for (int i = 0; i < N - 1; i++) {
    vp[i + 1].second += vp[i].second;
  }
  //   for (int i = 0; i < vp.size(); i++)
  // {
  //   cout<<vp[i].first<<" "<<vp[i].second<<endl;
  // }
  int ANS = 0;
  for (int i = 1; i <= (int)vp.size() - 1; i++) {
    int l = i;
    int r;
    if (vp[i].first == 1) {
      r = l + 2 * K;
    } else {
      r = l + 2 * (K)-1;
    }
    l--;
    if (r >= vp.size())
      r = (int)vp.size() - 1;
    if (l >= vp.size())
      l = (int)vp.size() - 1;

    chmax(ANS, vp[r].second - vp[l].second);
  }
  cout << ANS << endl;

  return;
}
int32_t main(int32_t argc, const char *argv[]) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(11);
  solve();

  return 0;
}


Fixed submission:
#include <algorithm>
#include <array>
#include <assert.h>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <deque>
#include <float.h>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits.h>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <string.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

using namespace std;
#define int long long

#define I32_MAX 2147483647
#define I64_MAX 9223372036854775807LL
#define I64_MAX2 1223372036854775807LL
#define INF I64_MAX2
#define MOD 1000000007
// #define MOD 998244353
#define MEM_SIZE 10000
#define DEBUG_OUT true
#define ALL(x) (x).begin(), (x).end()

template <typename T> void DEBUG(T e) {
  if (DEBUG_OUT == false)
    return;
  std::cout << e << " ";
}
template <typename T> void DEBUG(const std::vector<T> &v) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T> void DEBUG(const std::vector<std::vector<T>> &vv) {
  if (DEBUG_OUT == false)
    return;
  for (const auto &v : vv) {
    DEBUG(v);
  }
}
template <class T, class... Ts> void DEBUG(T d, Ts... e) {
  if (DEBUG_OUT == false)
    return;
  DEBUG(d);
  DEBUG(e...);
}
template <class T> void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    abort();
  }
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

void solve(void) {

  int N, K;
  cin >> N;
  cin >> K;
  vector<pair<int, int>> vp;
  vp.emplace_back(-1, 0);
  for (int i = 0; i < N; i++) {
    char X;
    cin >> X;

    int x = X - '0';
    if (vp.empty() || vp.back().first != x) {
      vp.push_back(make_pair(x, 1));
    } else {
      vp.back().second++;
    }
  }

  for (int i = 0; i < vp.size(); i++) {
    vp[i + 1].second += vp[i].second;
  }
  //   for (int i = 0; i < vp.size(); i++)
  // {
  //   cout<<vp[i].first<<" "<<vp[i].second<<endl;
  // }
  int ANS = 0;
  for (int i = 1; i <= (int)vp.size() - 1; i++) {
    int l = i;
    int r;
    if (vp[i].first == 1) {
      r = l + 2 * K;
    } else {
      r = l + 2 * (K)-1;
    }
    l--;
    if (r >= vp.size())
      r = (int)vp.size() - 1;
    if (l >= vp.size())
      l = (int)vp.size() - 1;

    chmax(ANS, vp[r].second - vp[l].second);
  }
  cout << ANS << endl;

  return;
}
int32_t main(int32_t argc, const char *argv[]) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cout << std::fixed;
  std::cout << std::setprecision(11);
  solve();

  return 0;
}