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| #include <bits/stdc++.h>
#define R register
#define ll long long
#define pair std::pair<int, int>
#define mp(i, j) std::make_pair(i, j)
#define meow(cat...) fprintf(stderr, cat)
#define sum(a, b, mod) (((a) + (b)) % mod)
const int MaxN = 2e5 + 10;
const int MaxM = 5e5 + 10;
struct Modify
{
int x, y;
} p[MaxM];
struct Operation
{
int op, x, y, v, id;
} op[MaxM];
struct Query
{
int x, y, t, id;
} q[MaxM], lq[MaxM], rq[MaxM];
std::vector<int> v[MaxM << 2];
int cnt, ans[MaxM], Ans[MaxM]; pair st[MaxM];
std::unordered_map<int, int> tim[MaxN];
int n, m, top, num, maxv, fa[MaxN], rk[MaxN];
int getf(int x)
{
if (x == fa[x])
return fa[x];
return getf(fa[x]);
}
void del(int cur)
{
while (top > cur)
{
pair pre = st[top--];
fa[pre.first] = pre.first;
rk[pre.first] = pre.second;
}
}
void merge(int x, int y)
{
x = getf(x), y = getf(y);
if (x == y) return;
if (rk[x] < rk[y]) std::swap(x, y);
fa[y] = x, st[++top] = mp(y, rk[y]);
if (rk[x] == rk[y])
st[++top] = mp(x, ++rk[x]);
}
void modify(int id, int l, int r, int ql, int qr, int pos)
{
if (ql <= l && r <= qr)
return (void)v[id].push_back(pos);
int mid = (l + r) >> 1;
if (ql <= mid) modify(id << 1, l, mid, ql, qr, pos);
if (qr > mid) modify(id << 1 | 1, mid + 1, r, ql, qr, pos);
}
inline int read()
{
int x = 0;
char ch = getchar();
while (ch > '9' || ch < '0')
ch = getchar();
while (ch <= '9' && ch >= '0')
x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
return x;
}
void solve(int id, int l, int r, int st, int ed)
{
if(st > ed) return; int cur = top;
for(int i = 0; i < v[id].size(); i++)
merge(p[v[id][i]].x, p[v[id][i]].y);
if(l == r)
{
for(int i = st; i <= ed; i++)
ans[q[i].id] = (getf(q[i].x) == getf(q[i].y));
return;
}
int mid = (l + r) >> 1, lt = 0, rt = 0;
for(int i = st; i <= ed; i++)
if(q[i].t <= mid) lq[++lt] = q[i];
else rq[++rt] = q[i];
for(int i = 1; i <= lt; i++) q[st + i - 1] = lq[i];
for(int i = 1; i <= rt; i++) q[st + i + lt - 1] = rq[i];
solve(id << 1, l, mid, st, st + lt - 1);
solve(id << 1 | 1, mid + 1, r, st + lt, ed), del(cur);
}
int main()
{
n = read(), m = read(), memset(Ans, -1, sizeof(Ans));
for(int i = 1; i <= m; i++)
{
op[i].op = read(), op[i].x = read() + 1, op[i].y = read() + 1, op[i].id = i;
if(op[i].op == 0) op[i].v = read(), maxv = std::max(maxv, op[i].v);
if(op[i].x > op[i].y) std::swap(op[i].x, op[i].y);
}
for(int V = 0; V <= maxv; V++)
{
for(int i = 1; i <= n; i++)
tim[i].clear(); cnt = num = top = 0;
for(int i = 1; i <= n; i++) fa[i] = i, rk[i] = 1;
for(int i = 1; i <= m * 4; i++) v[i].clear();
for(int i = 1; i <= m; i++)
{
int x = op[i].x, y = op[i].y;
if(op[i].op == 0 && op[i].v <= V) tim[x][y] = i;
else if (op[i].op == 1 && tim[x][y])
{
modify(1, 1, m, tim[x][y], i, ++cnt);
p[cnt] = (Modify) {x, y}, tim[x][y] = 0;
}
else if(op[i].op == 2) q[++num] = (Query) {x, y, i, num};
}
for(int i = 1; i <= n; i++)
for(auto x : tim[i])
if(x.second)
{
modify(1, 1, m, x.second, m, ++cnt);
p[cnt] = (Modify) {i, x.first};
}
solve(1, 1, m, 1, num);
for(int i = 1; i <= num; i++)
{
if(ans[i] && Ans[i] == -1)
Ans[i] = V;
ans[i] = 0;
}
}
for(int i = 1; i <= num; i++)
printf("%d\n", Ans[i]);
return 0;
}
|