Submission #567148

#	Time	Username	Problem	Language	Result	Execution time	Memory
567148		dantoh000	Jail (JOI22_jail)	C++14	61 / 100	5068 ms	27776 KiB

jail

#include <bits/stdc++.h>
using namespace std;
int q;
int n,m;
int s[120005], t[120005];
int p[120005][18];
int d[120005];
vector<int> G2[120005];
vector<int> G[120005];
int vis[120005];
int lca(int x, int y){
    ///printf("LCA %d %d\n",x,y);
    if (d[x] > d[y]) swap(x,y);
    int diff = d[y]-d[x];
    for (int k = 0; k < 18; k++){
        if (diff>>k&1) {
            y = p[y][k];
        }
    }
    if (x == y) return x;
    for (int k = 17; k >= 0; k--){
        if (p[x][k] && p[y][k] && p[x][k] != p[y][k]){
            x = p[x][k];
            y = p[y][k];
        }
    }
    assert(p[x][0] == p[y][0]);
    return p[x][0];
}
void dfs(int u, int p_){
    p[u][0] = p_;
    for (auto v:  G[u]){
        if (v == p_) continue;
        d[v] = d[u]+1;
        dfs(v,u);

    }
}
bool check(int x, int y, int z){
    int r = lca(x,y);
    return (lca(r,z) == r) && (lca(x,z) == z || lca(y,z) == z);
}
bool dfs2(int u){
    vis[u] = 2;
    bool can = true;
    for (auto v : G2[u]){
        if (vis[v] == 2) return false;
        else if (vis[v] == 0){
            can &= dfs2(v);
        };
    }
    vis[u] = 1;
    return can;
}
int main(){
    scanf("%d",&q);
    while (q--){
        scanf("%d",&n);
        for (int i = 1; i <= n; i++) G[i].clear();
        for (int i = 1,a,b; i < n; i++){
            scanf("%d%d",&a,&b);
            G[a].push_back(b);
            G[b].push_back(a);
        }
        d[1] = 0;
        dfs(1,0);
        for (int k = 1; k < 18; k++){
            for (int i = 1; i <= n; i++){
                p[i][k] = p[p[i][k-1]][k-1];
            }
        }
        scanf("%d",&m);
        for (int i = 0; i < m; i++){
            scanf("%d%d",&s[i],&t[i]);
        }
        for (int i = 0; i < m; i++) G2[i].clear();
        for (int i = 0; i < m; i++){
            for (int j = 0; j < m; j++){
                if (i == j) continue;
                if (check(s[i], t[i], s[j])){
                    ///printf("%d before %d\n",j,i);
                    G2[i].push_back(j);
                }
                if (check(s[i], t[i], t[j])){
                    ///printf("%d before %d\n",i,j);
                    G2[j].push_back(i);
                }
            }
        }
        bool can = true;
        fill(vis,vis+m, 0);
        for (int i = 0; i < m; i++){
            if (vis[i] == 0){
                can &= dfs2(i);
            }
        }
        if (can){
            printf("Yes\n");
        }
        else printf("No\n");

    }

}

Compilation message (stderr)

jail.cpp: In function 'int main()':
jail.cpp:56:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     scanf("%d",&q);
      |     ~~~~~^~~~~~~~~
jail.cpp:58:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |         scanf("%d",&n);
      |         ~~~~~^~~~~~~~~
jail.cpp:61:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |             scanf("%d%d",&a,&b);
      |             ~~~~~^~~~~~~~~~~~~~
jail.cpp:72:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         scanf("%d",&m);
      |         ~~~~~^~~~~~~~~
jail.cpp:74:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |             scanf("%d%d",&s[i],&t[i]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 12 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23