Problem p01144 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, s, n) for (int i = s; i < (int)n; i++)
#define per(i, n) for (int i = n; i >= 0; i--)
#define ROF(i, s, n) for (int i = s; i >= (int)n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << "\\n"
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MP make_pair
#define EACH(i, n)                                                             \\
  for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#define SZ(a) int((a).size())
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())
#define CLR(a) memset((a), 0, sizeof(a))
#define NCLR(a) memset((a), -1, sizeof(a))
#define dump(x) cout << #x << " = " << (x) << "\\n";
#define debug(x)                                                               \\
  cout << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << "\\n";
#define sq(n) (n) * (n)
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef priority_queue<int> maxpq;
typedef priority_queue<int, vector<int>, greater<int>> minpq;
static const double EPS = 1e-10;
static const double PI = acos(-1.0);
static const int mod = 1000000007;
static const int INF = 1 << 25;
static const LL LL_INF = 1152921504606846976;
static const int dx[] = {-1, 0, 1, 0, 1, -1, 1, -1};
static const int dy[] = {0, -1, 0, 1, 1, 1, -1, -1};

int n, m;
vector<PII> _array;

int main() {
  while (~scanf("%d %d", &n, &m) && n) {
    _array.resize(n);
    for (int i = 0; i < n; i++) {
      scanf("%d %d", &_array[i].second, &_array[i].first);
    }
    sort(_array.rbegin(), _array.rend());
    for (int i = 0; i < n; i++) {
      if (m == 0) {
        break;
      }
      int use_m = min(m, _array[i].second);
      _array[i].second -= use_m;
      m -= use_m;
    }
    int ans = 0;
    for (int i = 0; i < n; i++) {
      ans += _array[i].first * _array[i].second;
    }
    printf("%d\\n", ans);
  }
  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, s, n) for (int i = s; i < (int)n; i++)
#define per(i, n) for (int i = n; i >= 0; i--)
#define ROF(i, s, n) for (int i = s; i >= (int)n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << "\\n"
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MP make_pair
#define EACH(i, n)                                                             \\
  for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#define SZ(a) int((a).size())
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())
#define CLR(a) memset((a), 0, sizeof(a))
#define NCLR(a) memset((a), -1, sizeof(a))
#define dump(x) cout << #x << " = " << (x) << "\\n";
#define debug(x)                                                               \\
  cout << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << "\\n";
#define sq(n) (n) * (n)
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef priority_queue<int> maxpq;
typedef priority_queue<int, vector<int>, greater<int>> minpq;
static const double EPS = 1e-10;
static const double PI = acos(-1.0);
static const int mod = 1000000007;
static const int INF = 1 << 25;
static const LL LL_INF = 1152921504606846976;
static const int dx[] = {-1, 0, 1, 0, 1, -1, 1, -1};
static const int dy[] = {0, -1, 0, 1, 1, 1, -1, -1};

int n;
LL m;
vector<pair<LL, LL>> _array;

int main() {
  while (~scanf("%d %d", &n, &m) && n) {
    _array.resize(n);
    LL ans = 0;
    for (int i = 0; i < n; i++) {
      scanf("%d %d", &_array[i].second, &_array[i].first);
    }
    sort(_array.rbegin(), _array.rend());
    uint now = 0;
    while (m || now == n) {
      LL d = _array[now].second;
      _array[now].second = max<LL>(0, d - m);
      m = max<LL>(0, m - d);
      now++;
    }
    for (int i = 0; i < n; i++) {
      ans += _array[i].first * _array[i].second;
    }
    printf("%d\\n", ans);
  }
  return 0;
}