hdu 2680 Choose the best route

BFS.....

#include<stdio.h>
#include<math.h>
#include<string.h>
#include<vector>
#include<algorithm>
using namespace std;
const int maxn = 1111;
vector<int>abc[maxn];
int ji[maxn], tt[maxn][maxn], yy[maxn];
struct aaa{
    int node, time;
}dt[maxn*maxn];
bool cmp(const aaa&a, const aaa&b){ return a.time < b.time; }
int main()
{
    int n, m, mubiao;
    while (~scanf("%d%d%d", &n, &m, &mubiao))
    {
        int i, j;
        for (i = 0; i < maxn; i++) for (j = 0; j < maxn; j++) tt[i][j] = 999999999;
        for (i = 0; i < maxn; i++) ji[i] = 999999999, abc[i].clear();
        for (i = 0; i < m; i++)
        {
            int u, v, t;
            scanf("%d%d%d", &u, &v, &t);
            if (t < tt[v][u])
            {
                tt[v][u] = t;
                abc[v].push_back(u);
            }
        }
        int dd; scanf("%d", &dd);
        for (i = 0; i < dd; i++) scanf("%d", &yy[i]);
        int b = 0;
        dt[0].node = mubiao;
        dt[0].time = 0;
        for (i = 0; i <= b; i++)
        {
            for (j = 0; j < abc[dt[i].node].size(); j++)
            {
                if (dt[i].time + tt[dt[i].node][abc[dt[i].node][j]] < ji[abc[dt[i].node][j]])
                {
                    b++;
                    dt[b].node = abc[dt[i].node][j];
                    dt[b].time = dt[i].time + tt[dt[i].node][abc[dt[i].node][j]];
                    ji[abc[dt[i].node][j]] = dt[i].time + tt[dt[i].node][abc[dt[i].node][j]];
                }
            }
        }
        int ans = 999999999;
        for (i = 0; i < dd; i++) if (ji[yy[i]] < ans) ans = ji[yy[i]];
        if (ans == 999999999) printf("-1\n");
        else printf("%d\n", ans);
    }
    return 0;
}