fork download
copy 
  1. // ~~ icebear ~~
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4.  
  5. typedef long long ll;
  6. typedef pair<int, int> ii;
  7. typedef pair<int, ii> iii;
  8.  
  9. template<class T>
  10.     bool minimize(T &a, const T &b) {
  11.         if (a > b) return a = b, true;
  12.         return false;
  13.     }
  14.  
  15. template<class T>
  16.     bool maximize(T &a, const T &b) {
  17.         if (a < b) return a = b, true;
  18.         return false;
  19.     }
  20.  
  21. #define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
  22. #define FORR(i,a,b) for(int i=(a); i>=(b); --i)
  23. #define REP(i, n) for(int i=0; i<(n); ++i)
  24. #define RED(i, n) for(int i=(n)-1; i>=0; --i)
  25. #define MASK(i) (1LL << (i))
  26. #define BIT(S, i) (((S) >> (i)) & 1)
  27. #define mp make_pair
  28. #define pb push_back
  29. #define fi first
  30. #define se second
  31. #define all(x) x.begin(), x.end()
  32. #define task "searoutes"
  33.  
  34. const int MOD = 1e9 + 7;
  35. const int inf = 1e9 + 27092008;
  36. const ll INF = 1e18 + 27092008;
  37. const int N = 2e5 + 5;
  38. int numNode, numEdge, numQuery;
  39. vector<ii> G[N];
  40. set<int> adj[N];
  41. stack<int> st;
  42. int num[N], low[N], timer, scc[N], numScc, vis[N];
  43.  
  44. void dfs(int u, int old_id, int T) {
  45.     vis[u] = T;
  46.     num[u] = low[u] = ++timer;
  47.     st.push(u);
  48.     for(ii x : G[u]) {
  49.         int v, i; tie(v, i) = x;
  50.         if (i == old_id) continue;
  51.         if (num[v]) minimize(low[u], num[v]);
  52.         else {
  53.             dfs(v, i, T);
  54.             minimize(low[u], low[v]);
  55.         }
  56.     }
  57.  
  58.     if (num[u] == low[u]) {
  59.         numScc++;
  60.         int v;
  61.         do {
  62.             v = st.top(); st.pop();
  63.             scc[v] = numScc;
  64.         } while(v != u);
  65.     }
  66. }
  67.  
  68. bool answer;
  69. struct IT {
  70.     int sz;
  71.     vector<int> node, lazy;
  72.     IT(int n = 0): sz(n), node(4 * n + 5, 0), lazy(4 * n + 5, 0) {}
  73.  
  74.     int combine(int x, int y) {
  75.         if (max(x, y) == inf) return inf;
  76.         if (x == y) return x;
  77.         if (x * y == 0) return (!x ? y : x);
  78.         return inf;
  79.     }
  80.  
  81.     void pushDown(int id) {
  82.         if (lazy[id]) {
  83.             node[id << 1] = combine(node[id << 1], lazy[id]);
  84.             node[id << 1 | 1] = combine(node[id << 1 | 1], lazy[id]);
  85.             lazy[id << 1] = combine(lazy[id << 1], lazy[id]);
  86.             lazy[id << 1 | 1] = combine(lazy[id << 1 | 1], lazy[id]);
  87.             lazy[id] = 0;
  88.         }
  89.     }
  90.  
  91.     void update(int id, int l, int r, int u, int v, int k) {
  92.         if (l > v || r < u) return;
  93.         if (u <= l && r <= v) {
  94.             node[id] = combine(node[id], k);
  95.             lazy[id] = combine(lazy[id], k);
  96.             return;
  97.         }
  98.         pushDown(id);
  99.         int mid = (l + r) >> 1;
  100.         update(id << 1, l, mid, u, v, k);
  101.         update(id << 1 | 1, mid + 1, r, u, v, k);
  102.         node[id] = combine(node[id << 1], node[id << 1 | 1]);
  103.     }
  104.  
  105.     int getNode(int id, int l, int r, int u, int v) {
  106.         if (l > v || r < u) return 0;
  107.         if (u <= l && r <= v) return node[id];
  108.         pushDown(id);
  109.         int mid = (l + r) >> 1;
  110.         return combine(getNode(id << 1, l, mid, u, v), getNode(id << 1 | 1, mid + 1, r, u, v));
  111.     }
  112. } it[N];
  113.  
  114. int head[N], par[N][20], h[N], len[N], pos[N], sz[N];
  115.  
  116. void hld(int u, int p, bool create_chain, bool is_head) {
  117.     if (!create_chain || p == -1) {
  118.         sz[u] = 1;
  119.         for(int v : adj[u]) if (v != p) {
  120.             par[v][0] = u;
  121.             h[v] = h[u] + 1;
  122.             hld(v, u, false, false);
  123.             sz[u] += sz[v];
  124.         }
  125.     }
  126.     if (create_chain == false) return;
  127.     head[u] = (is_head ? u : head[p]);
  128.     pos[u] = ++len[head[u]];
  129.     int hvy = 0;
  130.     for(int v : adj[u]) if (v != p && sz[v] > sz[hvy])
  131.         hvy = v;
  132.     for(int v : adj[u]) if (v != p)
  133.         hld(v, u, true, (v != hvy));
  134. }
  135.  
  136. int LCA(int u, int v) {
  137.     if (h[u] < h[v]) swap(u, v);
  138.     int s = h[u] - h[v];
  139.     RED(j, 20) if (BIT(s, j))
  140.         u = par[u][j];
  141.     if (u == v) return u;
  142.     RED(j, 20) if (par[u][j] != par[v][j]) {
  143.         u = par[u][j];
  144.         v = par[v][j];
  145.     }
  146.     return par[u][0];
  147. }
  148.  
  149. void modify(int u, int lca, int sign) {
  150.     while(head[u] != head[lca]) {
  151.         if (answer == false) return;
  152.         it[head[u]].update(1, 1, len[head[u]], 1, pos[u], sign);
  153.         u = par[head[u]][0];
  154.     }
  155.  
  156.     if (u != lca) {
  157. //        cout << "CUR : " << u << ' ' << lca << ' ' << sign << ' ' << pos[lca] + 1 << ' ' << pos[u] << ' ' << head[u] << '\n';
  158.         it[head[u]].update(1, 1, len[head[u]], pos[lca] + 1, pos[u], sign);
  159.     }
  160. }
  161.  
  162. void check(int u, int lca) {
  163.     while(head[u] != head[lca]) {
  164.         if (answer == false) return;
  165.         if (it[head[u]].getNode(1, 1, len[head[u]], 1, pos[u]) == inf)
  166.             answer = false;
  167.         u = par[head[u]][0];
  168.     }
  169.     if (u != lca && it[head[u]].getNode(1, 1, len[head[u]], pos[lca] + 1, pos[u]) == inf)
  170.         answer = false;
  171. }
  172.  
  173. void init(void) {
  174.     cin >> numNode >> numEdge >> numQuery;
  175.     FOR(i, 1, numEdge) {
  176.         int u, v;
  177.         cin >> u >> v;
  178.         G[u].pb(mp(v, i));
  179.         G[v].pb(mp(u, i));
  180.     }
  181.  
  182.     int cnt = 0;
  183.     FOR(i, 1, numNode) if (!num[i])
  184.         dfs(i, -1, ++cnt);
  185. }
  186.  
  187. void process(void) {
  188.     FOR(i, 1, numNode) for(ii v : G[i])
  189.         if (scc[i] != scc[v.fi])
  190.             adj[scc[i]].insert(scc[v.fi]);
  191.     FOR(i, 1, numScc) if (!pos[i])
  192.         hld(i, -1, true, true);
  193.     FOR(j, 1, 19) FOR(i, 1, numScc)
  194.         par[i][j] = par[par[i][j - 1]][j - 1];
  195.  
  196.     FOR(i, 1, numScc) if (i == head[i])
  197.         it[i] = IT(len[i]);
  198.     answer = true;
  199. //    cout << "DEBUG SCC : "; FOR(i, 1, numNode) cout << scc[i] << ' '; cout << '\n';
  200.  
  201.     FOR(i, 1, numQuery) {
  202.         int u, v;
  203.         cin >> u >> v;
  204.         if (vis[u] != vis[v]) answer = false;
  205.         if (!answer) continue;
  206.         u = scc[u]; v = scc[v];
  207.         if (u == v) continue;
  208.         int p = LCA(u, v);
  209. //        cout << "UPDATE : " << u << ' ' << p << ' ' << -1 << '\n';
  210. //        cout << "UPDATE : " << v << ' ' << p << ' ' << +1 << '\n';
  211.         modify(u, p, -1);
  212.         modify(v, p, +1);
  213.         check(u, p);
  214.         check(v, p);
  215.     }
  216.     cout << (answer ? "Yes\n" : "No\n");
  217. }
  218.  
  219. void reset() {
  220.     FOR(i, 1, numNode) {
  221.         G[i].clear();
  222.         adj[i].clear();
  223.         num[i] = low[i] = 0;
  224.         sz[i] = pos[i] = head[i] = len[i] = h[i] = vis[i] = 0;
  225.         it[i].node.clear();
  226.         it[i].lazy.clear();
  227.     }
  228.     numScc = timer = 0;
  229.     st = stack<int>();
  230. }
  231.  
  232. int main() {
  233.     ios_base::sync_with_stdio(0);
  234.     cin.tie(0); cout.tie(0);
  235.     if (fopen(task".inp", "r")) {
  236.         freopen(task".inp", "r", stdin);
  237.         freopen(task".out", "w", stdout);
  238.     }
  239.     int tc = 1;
  240.     cin >> tc;
  241.     while(tc--) {
  242.         init();
  243.         process();
  244.         reset();
  245.     }
  246.     return 0;
  247. }
  248.  
  249.  
Success #stdin #stdout 0.05s 45836KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Yes
https://ideone.com/CddJ8J
language:
C++14 (gcc 8.3)
created:
12 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!