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| #include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <utility>
#ifdef XLor
#define dbg(args...) do {cout << #args << " -> "; err(args);} while (0)
#else
#define dbg(...)
#endif
void err() {std::cout << std::endl;}
template<typename T, typename...Args>
void err(T a, Args...args){std::cout << a << ' '; err(args...);}
#define ms(a,b) memset(a,b,sizeof(a))
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
const int mod = 998244353;
const int inf = 1 << 30;
const int maxn = 200000 + 5;
int pre[maxn];
int find(int x) {
return x == pre[x] ? x : pre[x] = find(pre[x]);
}
void join(int x, int y) {
x = find(x); y = find(y);
if (x == y) return ;
pre[x] = y;
}
vector<int> edge[maxn];
int n, m, q;
int cnt, bel[maxn]; // important!
namespace Tarjan {
int tot, dfn[maxn], low[maxn], st[maxn], top, vis[maxn];
void clear(int n) {
tot = top = cnt = 0;
for (int i = 1; i <= n; i++) {
edge[i].clear(); dfn[i] = vis[i] = bel[i] = 0;
}
}
void dfs(int u, int f) {
dfn[u] = low[u] = ++tot;
st[++top] = u; vis[u] = 1;
int k = 0;
for (int& v: edge[u]) {
if (v == f && !k) {
k++; continue;
}
if (!dfn[v]) {
dfs(v, u); low[u] = min(low[u], low[v]);
} else if (vis[v]) low[u] = min(low[u], dfn[v]);
}
if (dfn[u] == low[u]) {
cnt++; int t = 0;
do {
t = st[top--];
bel[t] = cnt;
vis[t] = 0;
} while (t != u);
}
}
void scc(int n, vector<int> * g) {
for (int i = 1; i <= n; i++) if (!dfn[i]) Tarjan::dfs(i, 0);
for (int i = 1; i <= n; i++) g[i].clear();
for (int i = 1; i <= n; i++) {
int u = bel[i];
for (int& x: edge[i]) {
int v = bel[x];
if (u != v) {
g[u].push_back(v);
}
}
}
}
}
namespace Tree {
vector<int> block[maxn];
int tin[maxn], tout[maxn], vis[maxn], tot;
int dp[maxn][22], dep[maxn];
void dfs(int u, int fa){
tin[u] = ++tot;
vis[u] = 1;
dp[u][0] = fa;
dep[u] = dep[fa] + 1;
for (int& v: block[u]) {
if (v == fa) continue;
dfs(v, u);
}
tout[u] = tot;
}
int qlca(int x, int y){
if (dep[x] < dep[y]) swap(x, y);
int tmp = dep[x] - dep[y];
for (int i = 0; tmp; i++, tmp >>= 1)
if (tmp & 1) x = dp[x][i];
if (x == y) return x;
for (int i = 20; i >= 0; i--){
if (dp[x][i] != dp[y][i]){
x = dp[x][i]; y = dp[y][i];
}
}
return dp[x][0];
}
void init() {
for (int i = 0; i <= cnt; i++) {
vis[i] = 0; ms(dp[i], 0);
}
dep[0] = tot = 0;
for (int i = 1; i <= cnt; i++) if (!vis[i]) {
dfs(i, 0);
}
for (int j = 1; j < 20; j++)
for (int i = 1; i <= cnt; i++)
dp[i][j] = dp[dp[i][j - 1]][j - 1];
}
int check(int p, int u) {
return tin[p] <= tin[u] && tout[p] >= tout[u];
}
}
int main() {
int T; scanf("%d", &T);
while (T--) {
scanf("%d%d%d", &n, &m, &q);
Tarjan::clear(n);
for (int i = 1; i <= n; i++) {
pre[i] = i;
}
for (int i = 1, u, v; i <= m; i++) {
scanf("%d%d", &u, &v);
edge[u].push_back(v); edge[v].push_back(u);
join(u, v);
}
Tarjan::scc(n, Tree::block);
Tree::init();
while (q--) {
int u, v, w; scanf("%d%d%d", &u, &v, &w);
if (find(u) != find(v) || find(u) != find(w)) {
puts("No"); continue;
}
u = bel[u]; v = bel[v]; w = bel[w];
int g = Tree::qlca(v, w);
if (Tree::check(g, u)) {
if (Tree::check(u, v) || Tree::check(u, w)) puts("Yes");
else puts("No");
} else puts("No");
}
}
return 0;
}
|