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| #include <bits/stdc++.h> using namespace std; const int MAXN = 10100;
const int MAXM = 200100; typedef pair<int, int> pii; struct UFS {
int f[MAXN];
stack<pii> s; int finds(int x) {
while (x ^ f[x])
x = f[x];
return x;
} void unite(int x, int y) {
x = finds(x);
y = finds(y);
if (x != y) {
s.push({x, f[x]});
f[x] = y;
}
} void init(int b, int e) { // 初始化函数，范围为 [b, e)
for (int i = b; i < e; i++)
f[i] = i;
} void undo() {
f[s.top().first] = s.top().second;
s.pop();
}
}; struct SegTree {
vector<pii> data[MAXM << 2]; static inline int lson(int k) { return k << 1; } static inline int rson(int k) { return (k << 1) | 1; } static inline int fat(int l, int r) { return (l + r) >> 1; }
// add 函数对应于正常的线段树的 insert，但是稍微有些不同
void add(int k, int l, int r, int x, int y, const pii &value) {
if (l == x && r == y) {
data[k].push_back(value);
return;
}
int mid = fat(l, r);
if (y <= mid) {
add(lson(k), l, mid, x, y, value);
} else if (x > mid) {
add(rson(k), mid + 1, r, x, y, value);
} else {
add(lson(k), l, mid, x, mid, value);
add(rson(k), mid + 1, r, mid + 1, y, value);
}
}
}; UFS ufs;
SegTree segTree;
vector<pair<pii, int> > que;
int tar;
// 通过 dfs 的方式在线段树上移动
bool dfs(int k, int l, int r) {
// 当完成一次询问之后，需要跳出当前的叶子，即回溯。通过 goto 来使得回溯的过程会自动进入正确的叶子节点
rejudge:
int target = que[tar].second;
if (target == r && l == r) {
if (ufs.finds(que[tar].first.first) == ufs.finds(que[tar].first.second))
cout << "Yes" << endl;
else
cout << "No" << endl;
tar++;
return tar == que.size();// true 表示所有的询问已经结束，退出 dfs
}
int mid = SegTree::fat(l, r);
if (target <= mid) {
// for (auto &item: segTree.data[SegTree::lson(k)])
// ufs.unite(item.first, item.second);
for (int i = 0; i < segTree.data[SegTree::lson(k)].size(); ++i)
ufs.unite(segTree.data[SegTree::lson(k)][i].first, segTree.data[SegTree::lson(k)][i].second);
if (dfs(SegTree::lson(k), l, mid))
return true;
// for (auto &item: segTree.data[SegTree::lson(k)])
for (int i = 0; i < segTree.data[SegTree::lson(k)].size(); ++i)
ufs.undo();
if (que[tar].second > r)
return false;
goto rejudge;
} else {
// for (auto &item: segTree.data[SegTree::rson(k)])
// ufs.unite(item.first, item.second);
for (int i = 0; i < segTree.data[SegTree::rson(k)].size(); ++i)
ufs.unite(segTree.data[SegTree::rson(k)][i].first, segTree.data[SegTree::rson(k)][i].second);
if (dfs(SegTree::rson(k), mid + 1, r))
return true;
// for (auto &item: segTree.data[SegTree::rson(k)])
for (int i = 0; i < segTree.data[SegTree::rson(k)].size(); ++i)
ufs.undo();
if (que[tar].second > r)
return false;
goto rejudge;
}
} void solve() {
int n, m;
cin >> n >> m;
map<pii, int> mp;
for (int i = 0; i < m; ++i) {
string s;
int u, v;
cin >> s >> u >> v;
if (u > v) swap(u, v);
switch (s[0]) {
case 'Q':
// que.push_back({{u, v}, i + 1});
que.push_back(make_pair(make_pair(u, v), i + 1));
break;
case 'C':
// mp.insert({{u, v}, i + 1});
mp.insert(make_pair(make_pair(u, v), i + 1));
break;
case 'D': {
// auto iter = mp.find({u, v});
map<pii, int>::iterator iter = mp.find(make_pair(u, v));
// segTree.add(1, 1, m, iter->second, i, {u, v});
segTree.add(1, 1, m, iter->second, i, make_pair(u, v));
mp.erase(iter);
break;
}
}
}
map<pii, int>::iterator iter = mp.begin();
while (iter != mp.end()) {
segTree.add(1, 1, m, iter->second, m, iter->first);
iter++;
}
ufs.init(0, n + 1);
tar = 0;
// for (auto &item: segTree.data[1])
for (int i = 0; i < segTree.data[1].size(); ++i)
ufs.unite(segTree.data[1][i].first, segTree.data[1][i].second);
// ufs.unite(item.first, item.second);
dfs(1, 1, m);
return;
} int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
// cin.tie(nullptr);
// cout.tie(nullptr);
#ifdef ACM_LOCAL
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
long long test_index_for_debug = 1;
char acm_local_for_debug;
while (cin >> acm_local_for_debug) {
if (acm_local_for_debug == '$') exit(0);
cin.putback(acm_local_for_debug);
if (test_index_for_debug > 20) {
throw runtime_error("Check the stdin!!!");
}
auto start_clock_for_debug = clock();
solve();
auto end_clock_for_debug = clock();
cout << "Test " << test_index_for_debug << " successful" << endl;
cerr << "Test " << test_index_for_debug++ << " Run Time: "
<< double(end_clock_for_debug - start_clock_for_debug) / CLOCKS_PER_SEC << "s" << endl;
cout << "--------------------------------------------------" << endl;
}
#else
solve();
#endif
return 0;
}
|
