#include<bits/stdc++.h>
using namespace std;
int w[1000005];
vector<int> v[1000005];
int fa[10000005], tot;
struct node{
    int type, u, v;
};
struct point{
    int dep, dfn, size, son, top, fa;
}tree[10000005];
int find(int x) { return fa[x] == x ? x : fa[x] = find(fa[x]); }
int n, c[10000005];
//------------------------------------------------------------------------------

int lowbit(int x) { return (-x) & x; }
void add(int x, int v) { 
    for(; x <= n; x -= lowbit(x)) c[x] += v; 
}

int Ask(int x) {
    int ans = 0;
    for(; x > 0; x -= lowbit(x)) ans += c[x];
    return ans;
}

int Q(int l, int r) {
    return Ask(r) - Ask(l - 1);
}

//------------------------------------------------------------------------------
void dfs(int x, int fa) {
    tree[x].dep = tree[fa].dep + 1;
    tree[x].size = 1; tree[x].fa = fa;
    for(int i = 0; i < v[x].size(); i++){
        int to = v[x][i];
        if(to == fa) continue; dfs(to, x);
        tree[x].size += tree[to].size;
        if(tree[tree[x].son].size < tree[to].size) tree[x].son = to;
    }
}

void dfs2(int x, int top) {
    tree[x].top = top; tree[x].dfn = ++tot; 
    if(tree[x].son == 0) return;
    dfs2(tree[x].son, top);
    for(int i = 0; i < v[x].size(); i++) {
        int to = v[x][i];
        if(to == tree[x].fa or to == tree[x].son) continue;
        dfs2(to, to);
    }

}

void update(int u, int val) {
    int x = w[u] - val;
    add(tree[u].dfn, x);
    w[u] = val;
} 

int query(int x, int y) {
    int ans = 0;
    while(tree[x].top != tree[y].top) {
        if(tree[tree[x].top].dep < tree[tree[y].top].dep) swap(x, y);
        ans += Q(tree[tree[x].top].dfn, tree[x].dfn);
        x = tree[tree[x].top].fa;
    }
    if(tree[x].dep > tree[y].dep) swap(x, y);
    return ans + Q(tree[x].dfn, tree[y].dfn);
}

//------------------------------------------------------------------------------
vector<node> ask;
int main(){
    //freopen("in.in", "r", stdin);
    //freopen("out.out", "w", stdout);
    cin >> n;
    for(int i = 1; i <= n; i++) cin >> w[i];
    int m; cin >> m;
    while(m --){
        string s; int a, b; 
        cin >> s >> a >> b;
        if(s[0] == 'b') {
            ask.push_back((node){1, a, b});
            v[a].push_back(b); v[b].push_back(a);
        } 
        else if(s[0] == 'p') ask.push_back((node){2, a, b});
        else ask.push_back((node){3, a, b});
    }
    for(int i = 1; i <= n; i++) if(tree[i].dep == 0) dfs(i, 0), dfs2(i, i);
    for(int i = 1; i <= n; i++) add(tree[i].dfn, w[i]);
    for(int i = 1; i <= n; i++) fa[i] = i;
    for(int i = 0; i < ask.size(); i++) {
        if(ask[i].type == 1) {
            int u = find(ask[i].u), v = find(ask[i].v);
            if(u != v) cout << "yes\n";
            else {
                cout << "no\n";
                fa[u] = v;
            }
        }  
        else if(ask[i].type == 2) update(ask[i].v, ask[i].v);
        else {
            int u = find(ask[i].u), v = find(ask[i].v);
            if(u != v) cout << "impossible\n";
            else {
                cout << query(u, v) << "\n";
            }
        }
    }
}

样例输入到第9次操作就卡死了