Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<stack>

#include<cstring>

using namespace std;

int n,m,q;

#define MAXN 100010

#define MAXM 500010

struct edge

{

    int u,v,w;

}e[MAXM];

bool cmp_s(edge x,edge y){return x.w > y.w;}

int f[MAXN];

int find(int x){return (f[x] == 0 ? x : f[x] = find(f[x]));}

#define INF 0x3f3f3f3f

struct node

{

    int c[2],fa,v,mx;

    bool rev;

    node(){v = mx = INF;rev = false;}

}t[MAXN + MAXM];

void maintain(int k){t[k].mx = min(t[k].v,min(t[t[k].c[0]].mx,t[t[k].c[1]].mx));return;}

void pushdown(int rt)

{

    if(t[rt].rev)

    {

        t[t[rt].c[0]].rev ^= 1;t[t[rt].c[1]].rev ^= 1;

        swap(t[rt].c[0],t[rt].c[1]);t[rt].rev = false;

    }

    return;

}

int id(int k){return (t[t[k].fa].c[0] == k ? 0 : 1);}

void connect(int k,int f,int p){t[k].fa = f;t[f].c[p] = k;return;}

bool isroot(int k){return (t[t[k].fa].c[0] != k && t[t[k].fa].c[1] != k);}

void rotate(int x)

{

    int y = t[x].fa,z = t[y].fa,fx = id(x),fy = id(y);

    if(!isroot(y))t[z].c[fy] = x;

    t[x].fa = z;

    connect(t[x].c[fx ^ 1],y,fx);

    connect(y,x,fx ^ 1);

    maintain(y);maintain(x);

    return;

}

stack<int> s;

void splay(int x)

{

    s.push(x);

    for(int i = x;!isroot(i);i = t[i].fa)s.push(t[i].fa);

    while(!s.empty()){pushdown(s.top());s.pop();}

    while(!isroot(x))

    {

        int y = t[x].fa;

        if(isroot(y)){rotate(x);break;}

        if(id(x) == id(y)){rotate(y);rotate(x);}

        else{rotate(x);rotate(x);}

    }

    return;

}

void access(int k){for(int i = 0;k;i = k,k = t[k].fa){splay(k);t[k].c[1] = i;maintain(k);}return;}

void makeroot(int k){access(k);splay(k);t[k].rev ^= 1;return;}

void link(int x,int y){makeroot(x);t[x].fa = y;return;}

int main()

{

    scanf("%d%d",&n,&m);

    for(int i = 1;i <= m;++i)

    {

        scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);

    }

    sort(e + 1,e + 1 + m,cmp_s);

    for(int i = 1;i <= m;++i)

    {

        if(find(e[i].u) != find(e[i].v))

        {

            f[find(e[i].u)] = find(e[i].v);

            t[i + n].v = t[i + n].mx = e[i].w;

            link(e[i].u,i + n);

            link(e[i].v,i + n);

        }

    }

    scanf("%d",&q);

    int a,b;

    for(int i = 1;i <= q;++i)

    {

        scanf("%d%d",&a,&b);

        if(find(a) != find(b))

        {

            puts("-1");

            continue;

        }

        makeroot(a);access(b);splay(b);

        printf("%d\n",t[b].mx);

    }

    return 0;

}