Problem p00459 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)

struct data {
  int l, r;
  data(int a, int b) : l(a), r(b) {}
  data() {}
};

int N, M;
int p, q, r;
int x[5001], y[5001];

int solve() {
  vector<data> L;
  L.push_back(data(1, N));
  x[M] = p - 1, y[M] = q;
  REP(i, M + 1) {
    vector<data> a, b, c;
    int sum = 0;
    int pos;
    for (int j = 0; j < L.size(); j++) {
      data d = L[j];
      if (x[i] == 0)
        break;
      if (sum + (d.r - d.l + 1) <= x[i]) {
        a.push_back(d);
        sum += (d.r - d.l + 1);
        pos = j + 1;
        if (sum == x[i])
          break;
      } else {
        a.push_back(data(d.l, x[i] + d.l - 1 - sum));
        // cout<<"**** "<<d.l<<" "<<x[i]+d.l-1-sum<<endl<<endl;
        L[j] = data(x[i] + d.l - sum, d.r);
        pos = j;
        break;
      }
    }
    sum = x[i];
    for (int j = pos; j < L.size(); j++) {
      data d = L[j];
      if (x[i] == y[i])
        break;
      if (sum + (d.r - d.l + 1) <= y[i]) {
        b.push_back(d);
        sum += (d.r - d.l + 1);
        pos = j + 1;
        if (sum == y[i])
          break;
      } else {
        b.push_back(data(d.l, y[i] + d.l - 1 - sum));
        L[j] = data(y[i] - sum + d.l, d.r);
        pos = j;
        break;
      }
    }
    L.erase(L.begin(), L.begin() + pos);
    if (i == M) {
      L = b;
      break;
    }
    L.insert(L.end(), b.begin(), b.end());
    L.insert(L.end(), a.begin(), a.end());
    // cout<<endl;EACH(it,L)cout<<it->l<<" "<<it->r<<endl;
  }
  // cout<<endl;EACH(it,L)cout<<it->l<<" "<<it->r<<endl;
  int cnt = 0;
  EACH(it, L) {
    int l = it->l, u = it->r;
    if (l > r)
      continue;
    if (u <= r)
      cnt += u - l + 1;
    else {
      cnt += r - l + 1;
    }
  }
  return cnt;
}

int main() {
  while (cin >> N, N) {
    cin >> M;
    cin >> p >> q >> r;
    REP(i, M) cin >> x[i] >> y[i];
    cout << solve() << endl;
  }
  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)

struct data {
  int l, r;
  data(int a, int b) : l(a), r(b) {}
  data() {}
};

int N, M;
int p, q, r;
int x[5001], y[5001];

int solve() {
  list<data> L;
  L.push_back(data(1, N));
  x[M] = p - 1, y[M] = q;
  REP(i, M + 1) {
    list<data> a, b, c;
    int sum = 0;
    list<data>::iterator it = L.begin();
    while (true) {
      data d = *it;
      if (x[i] == 0)
        break;
      if (sum + (d.r - d.l + 1) <= x[i]) {
        a.push_back(d);
        L.pop_front();
        it = L.begin();
        sum += (d.r - d.l + 1);
        if (sum == x[i])
          break;
      } else {
        a.push_back(data(d.l, x[i] + d.l - 1 - sum));
        // cout<<"**** "<<d.l<<" "<<x[i]+d.l-1-sum<<endl<<endl;
        L.pop_front();
        L.push_front(data(x[i] + d.l - sum, d.r));
        it = L.begin();
        break;
      }
    }
    sum = x[i];
    while (true) {
      data d = *it;
      if (x[i] == y[i])
        break;
      if (sum + (d.r - d.l + 1) <= y[i]) {
        b.push_back(d);
        L.pop_front();
        it = L.begin();
        sum += (d.r - d.l + 1);
        if (sum == y[i])
          break;
      } else {
        b.push_back(data(d.l, y[i] + d.l - 1 - sum));
        L.pop_front();
        L.push_front(data(y[i] - sum + d.l, d.r));
        it = L.begin();
        break;
      }
    }
    if (i == M) {
      L = b;
      break;
    }
    L.insert(L.end(), b.begin(), b.end());
    L.insert(L.end(), a.begin(), a.end());
    // cout<<endl;EACH(it,L)cout<<it->l<<" "<<it->r<<endl;
  }
  // cout<<endl;EACH(it,L)cout<<it->l<<" "<<it->r<<endl;
  int cnt = 0;
  EACH(it, L) {
    int l = it->l, u = it->r;
    if (l > r)
      continue;
    if (u <= r)
      cnt += u - l + 1;
    else {
      cnt += r - l + 1;
    }
  }
  return cnt;
}

int main() {
  while (cin >> N, N) {
    cin >> M;
    cin >> p >> q >> r;
    REP(i, M) cin >> x[i] >> y[i];
    cout << solve() << endl;
  }
  return 0;
}