This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
//#define int ll
const int inf = int(1e9);
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> p2;
#define rep(i, high) for (int i = 0; i < high; i++)
#define repp(i, low, high) for (int i = low; i < high; i++)
#define repe(i, container) for (auto& i : container)
#define sz(container) ((int)container.size())
#define all(x) begin(x),end(x)
#define ceildiv(x,y) ((x + y - 1) / (y))
inline void fast() { ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); }
#define _LOCAL _DEBUG
#if _LOCAL
#define assert(x) if (!(x)) __debugbreak()
#endif
const int maxn = int(1.5e5);
int tin[maxn];
int tout[maxn];
int timer = 0;
int up[maxn][18];
bool upincreasing[maxn][18];
bool updecreasing[maxn][18];
int upmax[maxn][18];
int upv[maxn];
void dfs(int u, int p, int p1, int _p2, vector<vector<p2>>& edges)
{
tin[u] = timer++;
up[u][0] = p;
upmax[u][0] = upv[u];
upincreasing[u][0] = upmax[u][0] < upmax[p][0] || p==0 || u==0;
updecreasing[u][0] = upmax[u][0] > upmax[p][0] || p==0 || u==0;
repp(d,1,18)
{
int mid = up[u][d - 1];
up[u][d] = up[mid][d - 1];
upmax[u][d] = max(upmax[u][d - 1], upmax[mid][d - 1]);
upincreasing[u][d] = upincreasing[u][d - 1] && upincreasing[mid][d - 1] && (upmax[mid][0] < upmax[up[mid][0]][0] || up[mid][0] ==0||mid==0);
updecreasing[u][d] = updecreasing[u][d - 1] && updecreasing[mid][d - 1] && (upmax[mid][0] > upmax[up[mid][0]][0] || up[mid][0] ==0||mid==0);
}
repe(e, edges[u]) if (e.first != p)
{
upv[e.first] = e.second;
dfs(e.first, u, p1, _p2, edges);
}
tout[u] = timer++;
}
bool isancestor(int a, int b)
{
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
int pathmax(int a, int b)
{
if (isancestor(a, b)) return -1;
int ret = -1;
for (int d = 17; d >= 0; d--)
{
if (!isancestor(up[a][d], b))
{
ret = max(ret, upmax[a][d]);
a = up[a][d];
}
}
return max(ret, upmax[a][0]);
}
signed main()
{
fast();
//ifstream in("C:\\Users\\Matis\\desktop\\comp_prog\\x64\\debug\\in.txt");
//cin.rdbuf(in.rdbuf());
int n, q;
cin >> n >> q;
vvi queries;
int t = 0;
vector<vector<p2>> edges(n);
rep(i, n + q - 1)
{
char c;
cin >> c;
if (c=='S')
{
int a, b;
cin >> a >> b;
a--; b--;
edges[a].emplace_back(b, t);
edges[b].emplace_back(a, t);
t++;
}
else if (c=='Q')
{
int a, b;
cin >> a >> b;
a--; b--;
queries.push_back({ 0, b, a, t-1 });
}
else
{
int c;
cin >> c;
c--;
queries.push_back({ 1, c, -1, t-1 });
}
}
dfs(0, 0, -1, -1, edges);
auto getmax = [&](int a, int b)
{
return max(pathmax(a, b), pathmax(b, a));
};
auto pathgood = [&](int a, int b, int t)
{
if (getmax(a, b) > t) return false;
// all edges <= t
// from b->lca increasing
// from a->lca decreasing
bool good = 1;
int u = b;
int prev = inf;
for (int d = 17; d >= 0; d--)
{
if (!isancestor(up[u][d],a))
{
good &= updecreasing[u][d];
u = up[u][d];
}
}
if (!isancestor(u,a))
{
prev = upmax[u][0];
}
u = a;
int v = -1;
for (int d = 17; d >= 0; d--)
{
if (!isancestor(up[u][d], b))
{
good &= upincreasing[u][d];
u = up[u][d];
}
}
if (!isancestor(u, b))
{
v = upmax[u][0];
}
return good && (v < prev);
};
repe(q, queries)
{
int type=q[0], a=q[1], b=q[2], t=q[3];
if (type==0)
{
cout << (pathgood(a, b, t) ? "yes" : "no") << "\n";
}
else
{
}
}
return 0;
}
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