Problem p00212 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define REP(i, n) for (int i = 0; i < n; i++)
#define RPA(i, s, e) for (int i = s; i <= e; i++)
#define RPD(i, s, e) for (int i = s; i >= e; i--)
#define PB(a) push_back(a)
#define MP(i, s) make_pair(i, s)
#define ALL(a) (a).begin(), (a).end()
#define PRT(a) cout << (a) << endl

typedef pair<int, int> P;

struct edge {
  int to, cost;
};

const int INF = 1000000009;
const int MAX_V = 111;
const int MAX_C = 15;
vector<edge> G[MAX_V];

int c, n, m, s, d;
int p, q, r;
int dp[MAX_C][MAX_V];

void add_edge(int from, int to, int cost) {
  edge e1 = {to, cost};
  edge e2 = {from, cost};
  G[from].PB(e1);
  G[to].PB(e2);
}

void dijkstra(int f, int t, int k) {
  REP(j, n) dp[k][j] = INF;

  priority_queue<P, vector<P>, greater<P>> que;
  que.push(MP(0, f));
  dp[k][f] = 0;

  while (!que.empty()) {
    P p = que.top();
    que.pop();

    int v = p.second;
    REP(i, G[v].size()) {
      edge &e = G[v][i];
      int minval = dp[k][v] + e.cost;
      if (k > 0)
        minval = min(minval, dp[k - 1][v] + e.cost / 2);
      if (dp[k][e.to] > minval) {
        dp[k][e.to] = minval;
        que.push(P(minval, e.to));
      }
    }
  }
}

void solve() {
  RPA(i, 0, c) { dijkstra(s, d, i); }
  PRT(dp[c][d]);
}

void coding() {
  while (scanf("%d%d%d%d%d", &c, &n, &m, &s, &d) != EOF) {
    if (c == 0 && n == 0 && m == 0 && s == 0 && d == 0)
      break;

    s--;
    d--;
    REP(i, n) G[i].clear();

    REP(i, m) {
      scanf("%d%d%d", &p, &q, &r);
      p--;
      q--;
      add_edge(p, q, r);
    }
    solve();
  }
}

// #define _LOCAL_TEST

int main() {
#ifdef _LOCAL_TEST
  freopen("a.in", "r", stdin);
#endif

  coding();

#ifdef _LOCAL_TEST
  cout << endl;
  cout << "This is local test" << endl;
  cout << "Do not forget to comment out _LOCAL_TEST" << endl;
#endif
}

Error: 0

Fixed submission:

#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define REP(i, n) for (int i = 0; i < n; i++)
#define RPA(i, s, e) for (int i = s; i <= e; i++)
#define RPD(i, s, e) for (int i = s; i >= e; i--)
#define PB(a) push_back(a)
#define MP(i, s) make_pair(i, s)
#define ALL(a) (a).begin(), (a).end()
#define PRT(a) cout << (a) << endl

typedef pair<int, int> P;

struct edge {
  int to, cost;
};

const int INF = 1000000009;
const int MAX_V = 101;
const int MAX_C = 11;
vector<edge> G[MAX_V];

int c, n, m, s, d;
int p, q, r;
int dp[MAX_C][MAX_V];

void add_edge(int from, int to, int cost) {
  edge e1 = {to, cost};
  edge e2 = {from, cost};
  G[from].PB(e1);
  G[to].PB(e2);
}

void dijkstra(int f, int t, int k) {
  REP(j, m) dp[k][j] = INF;

  priority_queue<P, vector<P>, greater<P>> que;
  que.push(MP(0, f));
  dp[k][f] = 0;

  while (!que.empty()) {
    P p = que.top();
    que.pop();

    int v = p.second;
    REP(i, G[v].size()) {
      edge &e = G[v][i];
      int minval = dp[k][v] + e.cost;
      if (k > 0)
        minval = min(minval, dp[k - 1][v] + e.cost / 2);
      if (dp[k][e.to] > minval) {
        dp[k][e.to] = minval;
        que.push(P(minval, e.to));
      }
    }
  }
}

void solve() {
  RPA(i, 0, c) { dijkstra(s, d, i); }
  PRT(dp[c][d]);
}

void coding() {
  while (scanf("%d%d%d%d%d", &c, &n, &m, &s, &d) != EOF) {
    if (c == 0 && n == 0 && m == 0 && s == 0 && d == 0)
      break;

    s--;
    d--;
    REP(i, m) G[i].clear();

    REP(i, m) {
      scanf("%d%d%d", &p, &q, &r);
      p--;
      q--;
      add_edge(p, q, r);
    }

    solve();
  }
}

// #define _LOCAL_TEST

int main() {
#ifdef _LOCAL_TEST
  freopen("a.in", "r", stdin);
#endif

  coding();

#ifdef _LOCAL_TEST
  cout << endl;
  cout << "This is local test" << endl;
  cout << "Do not forget to comment out _LOCAL_TEST" << endl;
#endif
}