I can not find a reason as to why I am getting a SIGABRT error in this code. The constraints are n,m<=100. Can someone please help?

Lucius Dungeon http://www.spoj.com/problems/BYTESE1/

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
typedef pair<int,int> ii;

vector<ii> graph[10005];
int C[105][105];
int D[10005];
int n,m;

set<ii> S;

void dijkstra(int st)
{
    S.insert(ii(C[0][0],st));
    
    ii top;
    int u,v,c,i;
    D[st]=C[0][0];
    
    while(!S.empty())
    {
        top = *S.begin();
        S.erase(S.begin());
        c = top.f;
        u = top.s;
        
        for(i=0;i<graph[u].size();i++)
        {
            ii x = graph[u][i];
            v = x.f;
            
            if(D[v]>=D[u]+x.s)
            {
                if(D[v]!=1e7)
                    S.erase(S.find(ii(D[v],v)));
                D[v]=D[u]+x.s;
                S.insert(ii(D[v],v));
            }
        }
    }
    
}



int main(int argc, const char * argv[])
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int i,j,t,u,k,l,a,b,T,d;
    
    cin>>t;
    
    while(t--)
    {
        cin>>n>>m;
        for(i=0;i<n;i++)
            for(j=0;j<m;j++)
                cin>>C[i][j];
        
        cin>>a>>b>>T;
        
        a--;
        b--;
        
        for(i=0;i<m*n+1;i++)
        {
            graph[i].clear();
            D[i]=1e7;
        }
        
        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                u = i*m + j;
                
                for(k=max(i-1,0);k<=min(i+1,n-1);k++)
                {

                    if(k==i)
                        continue;
                    graph[u].pb(ii(k*m+j,C[k][j]));
                    
                }
                
                for(l=max(j-1,0);l<=min(j+1,m-1);l++)
                {
                    if(l==j)
                        continue;
                    graph[u].pb(ii(i*m+l,C[i][l]));
                }

            }
        }
        
        dijkstra(0);
        
        d = D[a*m + b];
        
        if(d<=T)
        {
            cout<<"YES\n";
            cout<<T-d<<"\n";
        }
        else
            cout<<"NO\n";
        
        
    }
    
    return 0;
}