This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#define DEBUG 0
#include <bits/stdc++.h>
using namespace std;
#if DEBUG
// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}
// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
    public:
        template<typename T>
        _Debug& operator,(T val) {
            cout << val << endl;
            return *this;
        }
};
#define debug _Debug(),
#else
#define printLine(l)
#define printLine2(l,c)
#define printVar(n)
#define printArr(a,l)
#define print2dArr(a,r,c)
#define print2dArr2(a,r,c,l)
#define debug
#endif
// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6
#define mp make_pair
#define pb push_back
// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;
// ---------- END OF TEMPLATE ----------
int N,M;
struct edge { int u,v,w; };
vector<edge> edges;
int opp(int a,int b) {
    return ((a < 2*M) && (b < 2*M) && ((a^b) == 1));
}
int X[100000];
int num;
vpii adjList[10000];
vi nodes;
int tree[1 << 12];
int build(int s,int e,int i) {
    if (s == e) return 0;
    int mid = (s+e) / 2;
    build(s,mid,2*i+1),build(mid+1,e,2*i+2);
    tree[i] = num++;
    if (s == mid) adjList[tree[i]].pb(mp(nodes[s],edges[nodes[s]].w));
    else adjList[tree[i]].pb(mp(tree[2*i+1],0));
    if (mid+1 == e) adjList[tree[i]].pb(mp(nodes[e],edges[nodes[e]].w));
    else adjList[tree[i]].pb(mp(tree[2*i+2],0));
    return 0;
}
int add(int s,int e,int as,int ae,int i,int u) {
    if ((s > ae) || (e < as)) return 0;
    else if ((s >= as) && (e <= ae)) {
        if (s == e) adjList[u].pb(mp(nodes[s],edges[nodes[s]].w));
        else adjList[u].pb(mp(tree[i],0));
        return 0;
    }
    int mid = (s+e) / 2;
    add(s,mid,as,ae,2*i+1,u),add(mid+1,e,as,ae,2*i+2,u);
    return 0;
}
priority_queue<pair<LLI,int> > H;
LLI dist2[10000];
LLI dist[4000][4000];
struct path { int eu,ev; LLI d; };
bool comp(path a,path b) {
    return a.d < b.d;
}
vector<path> paths[2001][2001];
int shorten(vector<path> &v) {
    int i;
    vector<path> v2;
    sort(v.begin(),v.end(),comp);
    while (!v.empty() && (v.back().d > 1e17)) v.pop_back();
    if (v.empty()) return 0;
    v2.pb(v[0]);
    int m1 = -1,m2 = -1;
    for (i = 1; i < v.size(); i++) {
        if (v[i].eu != v[0].eu) {
            if (m1 == -1) m1 = i;
            else if ((m2 == -1) && (v[i].ev != v[m1].ev)) m2 = i;
        }
    }
    if (m1 != -1) v2.pb(v[m1]),m1 = -1;
    if (m2 != -1) v2.pb(v[m2]),m2 = -1;
    for (i = 1; i < v.size(); i++) {
        if (v[i].ev != v[0].ev) {
            if (m1 == -1) m1 = i;
            else if ((m2 == -1) && (v[i].eu != v[m1].eu)) m2 = i;
        }
    }
    if (m1 != -1) v2.pb(v[m1]),m1 = -1;
    if (m2 != -1) v2.pb(v[m2]),m2 = -1;
    v = v2,v.shrink_to_fit();
    return 0;
}
vector<path> com(vector<path> a,vector<path> b) {
    int i,j;
    vector<path> c;
    for (i = 0; i < a.size(); i++) {
        for (j = 0; j < b.size(); j++) {
            if (!opp(a[i].ev,b[j].eu)) c.pb((path){a[i].eu,b[j].ev,a[i].d+b[j].d});
        }
    }
    shorten(c);
    return c;
}
vector<path> tree2[1 << 18];
int build2(int s,int e,int i) {
    if (s == e) {
        tree2[i] = paths[(s == 0) ? N:X[s-1]][X[s]];
        return 0;
    }
    int mid = (s+e) / 2;
    build2(s,mid,2*i+1),build2(mid+1,e,2*i+2);
    tree2[i] = com(tree2[2*i+1],tree2[2*i+2]);
    return 0;
}
int update2(int s,int e,int ai,int i) {
    if ((s > ai) || (e < ai)) return 0;
    else if (s == e) {
        tree2[i] = paths[(s == 0) ? N:X[s-1]][X[s]];
        return 0;
    }
    int mid = (s+e) / 2;
    update2(s,mid,ai,2*i+1),update2(mid+1,e,ai,2*i+2);
    tree2[i] = com(tree2[2*i+1],tree2[2*i+2]);
    return 0;
}
int main() {
    int i;
    int T,L;
    int A,B,C,P,Q;
    scanf("%d %d %d %d",&N,&M,&T,&L);
    for (i = 0; i < M; i++) {
        scanf("%d %d %d",&A,&B,&C);
        A--,B--;
        edges.pb((edge){A,B,C});
        edges.pb((edge){B,A,C});
    }
    for (i = 0; i < L; i++) scanf("%d",&X[i]),X[i]--;
    int j,k;
    num = edges.size();
    for (i = 0; i < N; i++) {
        vi v;
        for (j = 0; j < edges.size(); j++) {
            if (edges[j].u == i) nodes.pb(j);
            if (edges[j].v == i) v.pb(j);
        }
        build(0,(int) nodes.size()-1,0);
        for (j = 0; j < v.size(); j++) {
            for (k = 0; k < nodes.size(); k++) {
                if (edges[nodes[k]].v == edges[v[j]].u) break;
            }
            if (k < nodes.size()) {
                add(0,(int) nodes.size()-1,0,k-1,0,v[j]);
                add(0,(int) nodes.size()-1,k+1,(int) nodes.size()-1,0,v[j]);
            }
            else add(0,(int) nodes.size()-1,0,(int) nodes.size()-1,0,v[j]);
        }
        nodes.clear();
    }
    for (i = 0; i < edges.size(); i++) {
        for (j = 0; j < num; j++) dist2[j] = 1e18;
        dist2[i] = 0,H.push(mp(0,i));
        while (!H.empty()) {
            int u = H.top().second;
            LLI d = -H.top().first;
            H.pop();
            if (d > dist2[u]) continue;
            for (j = 0; j < adjList[u].size(); j++) {
                int v = adjList[u][j].first;
                if (d+adjList[u][j].second < dist2[v]) {
                    dist2[v] = d+adjList[u][j].second;
                    H.push(mp(-dist2[v],v));
                }
            }
        }
        for (j = 0; j < edges.size(); j++) dist[i][j] = dist2[j];
    }
    for (i = 0; i < num; i++) adjList[i].clear();
    for (i = 0; i < edges.size(); i++) {
        for (j = 0; j < edges.size(); j++) {
            if ((edges[i].u != edges[j].v) && (dist[i][j] < 1e18))
                paths[edges[i].u][edges[j].v].pb((path){i,j,dist[i][j]+edges[i].w});
        }
    }
    for (i = 0; i < N; i++) paths[N][i].pb((path){2*M+i,2*M+i,0});
    for (i = 0; i <= N; i++) {
        for (j = 0; j <= N; j++) shorten(paths[i][j]);
    }
    build2(0,L-1,0);
    for (i = 0; i < T; i++) {
        scanf("%d %d",&P,&Q);
        P--,Q--,X[P] = Q;
        update2(0,L-1,P,0);
        if (P < L-1) update2(0,L-1,P+1,0);
        if (tree2[0].empty()) printf("-1\n");
        else printf("%lld\n",tree2[0][0].d);
    }
    return 0;
}
Compilation message (stderr)
wild_boar.cpp: In function 'int shorten(std::vector<path>&)':
wild_boar.cpp:109:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 1; i < v.size(); i++) {
                 ~~^~~~~~~~~~
wild_boar.cpp:117:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 1; i < v.size(); i++) {
                 ~~^~~~~~~~~~
wild_boar.cpp: In function 'std::vector<path> com(std::vector<path>, std::vector<path>)':
wild_boar.cpp:131:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < a.size(); i++) {
                 ~~^~~~~~~~~~
wild_boar.cpp:132:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < b.size(); j++) {
                     ~~^~~~~~~~~~
wild_boar.cpp: In function 'int main()':
wild_boar.cpp:180:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < edges.size(); j++) {
                     ~~^~~~~~~~~~~~~~
wild_boar.cpp:185:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < v.size(); j++) {
                     ~~^~~~~~~~~~
wild_boar.cpp:186:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (k = 0; k < nodes.size(); k++) {
                         ~~^~~~~~~~~~~~~~
wild_boar.cpp:189:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if (k < nodes.size()) {
                 ~~^~~~~~~~~~~~~~
wild_boar.cpp:197:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < edges.size(); i++) {
                 ~~^~~~~~~~~~~~~~
wild_boar.cpp:206:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (j = 0; j < adjList[u].size(); j++) {
                         ~~^~~~~~~~~~~~~~~~~~~
wild_boar.cpp:214:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < edges.size(); j++) dist[i][j] = dist2[j];
                     ~~^~~~~~~~~~~~~~
wild_boar.cpp:217:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < edges.size(); i++) {
                 ~~^~~~~~~~~~~~~~
wild_boar.cpp:218:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < edges.size(); j++) {
                     ~~^~~~~~~~~~~~~~
wild_boar.cpp:167:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d",&N,&M,&T,&L);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
wild_boar.cpp:169:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d",&A,&B,&C);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~
wild_boar.cpp:174:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (i = 0; i < L; i++) scanf("%d",&X[i]),X[i]--;
                             ~~~~~~~~~~~~~~~~~^~~~~~~
wild_boar.cpp:230:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&P,&Q);
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