by hansang:

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=4e4+10;
struct node{
    LL x, y;
    node() {x=y=0;}
} d[N];
struct at{int u, v; LL l; char s[5];} a[N];
struct qt{int u, v, k, id;} b[N];
node operator+(node n1, node n2){
    n1.x+=n2.x; n1.y+=n2.y;
    return n1;
}
node operator-(node n1, node n2){
    n1.x-=n2.x; n1.y-=n2.y;
    return n1;
}
bool cmp(qt q1, qt q2){
    return q1.k<q2.k;
}
int fa[N]; LL ans[N]; bool v[N];
int findfa(int x){
    if(fa[x]==x) return fa[x];
    int f=fa[x];
    int tx=findfa(fa[x]);
    d[x]=d[x]+d[f];
    return fa[x]=tx;
}
void merge(int u, int v, LL l, char s[]){
    int tx=findfa(u), ty=findfa(v);
    if(tx==ty) return ;
    fa[tx]=ty; node no;
    if(s[0]=='E') no.x=0, no.y=l;
    if(s[0]=='S') no.x=-l, no.y=0;
    if(s[0]=='W') no.x=0, no.y=-l;
    if(s[0]=='N') no.x=l, no.y=0;
    d[tx]=no-d[u]+d[v];
}
int dis(node n1, node n2){
    return abs(n1.x-n2.x)+abs(n1.y-n2.y);
}
int main(){
    int n, q; scanf("%d%d", &n, &q);
    for(int i=1; i<=n; i++) fa[i]=i;
    for(int i=1; i<=q; i++){
        scanf("%d%d%lld%s", &a[i].u, &a[i].v, &a[i].l, a[i].s);
    }
    int m; scanf("%d", &m);
    for(int i=1; i<=m; i++){
        scanf("%d%d%d", &b[i].u, &b[i].v, &b[i].k);
        b[i].id=i;
    }
    sort(b+1, b+m+1, cmp);
    memset(v, 0, sizeof(v)); int now=0;
    for(int i=1; i<=m; i++){
        while(now<=b[i].k) merge(a[now].u, a[now].v, a[now].l, a[now].s), now++;
        int tx=findfa(b[i].u), ty=findfa(b[i].v);
        if(tx!=ty){
            ans[b[i].id]=-1;
        }
        else{
            ans[b[i].id]=dis(d[b[i].u], d[b[i].v]);
        }
    }
    for(int k=1; k<=m; k++) printf("%lld\n", ans[k]);
    return 0;
}

by hansang:

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=4e4+10;
struct node{
    LL x, y;
    node() {x=y=0;}
} d[N];
struct at{int u, v; LL l; char s[5];} a[N];
struct qt{int u, v, k, id;} b[N];
node operator+(node n1, node n2){
    n1.x+=n2.x; n1.y+=n2.y;
    return n1;
}
node operator-(node n1, node n2){
    n1.x-=n2.x; n1.y-=n2.y;
    return n1;
}
bool cmp(qt q1, qt q2){
    return q1.k<q2.k;
}
int fa[N]; LL ans[N]; bool v[N];
int findfa(int x){
    if(fa[x]==x) return fa[x];
    int f=fa[x];
    int tx=findfa(fa[x]);
    d[x]=d[x]+d[f];
    return fa[x]=tx;
}
void merge(int u, int v, LL l, char s[]){
    int tx=findfa(u), ty=findfa(v);
    if(tx==ty) return ;
    fa[tx]=ty; node no;
    if(s[0]=='E') no.x=0, no.y=l;
    if(s[0]=='S') no.x=-l, no.y=0;
    if(s[0]=='W') no.x=0, no.y=-l;
    if(s[0]=='N') no.x=l, no.y=0;
    d[tx]=no-d[ u ]+d[v];
}
int dis(node n1, node n2){
    return abs(n1.x-n2.x)+abs(n1.y-n2.y);
}
int main(){
    int n, q; scanf("%d%d", &n, &q);
    for(int i=1; i<=n; i++) fa[i]=i;
    for(int i=1; i<=q; i++){
        scanf("%d%d%lld%s", &a[i].u, &a[i].v, &a[i].l, a[i].s);
    }
    int m; scanf("%d", &m);
    for(int i=1; i<=m; i++){
        scanf("%d%d%d", &b[i].u, &b[i].v, &b[i].k);
        b[i].id=i;
    }
    sort(b+1, b+m+1, cmp);
    memset(v, 0, sizeof(v)); int now=0;
    for(int i=1; i<=m; i++){
        while(now<=b[i].k) merge(a[now].u, a[now].v, a[now].l, a[now].s), now++;
        int tx=findfa(b[i].u), ty=findfa(b[i].v);
        if(tx!=ty){
            ans[b[i].id]=-1;
        }
        else{
            ans[b[i].id]=dis(d[b[i].u], d[b[i].v]);
        }
    }
    for(int k=1; k<=m; k++) printf("%lld\n", ans[k]);
    return 0;
}