Submission #1030977

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030977		dpsaveslives	Bosses (BOI16_bosses)	C++17	100 / 100	1036 ms	1148 KiB

bosses

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5010;
vector<int> adj[MAXN];
vector<int> graph[MAXN],st;
int N,ans,cnt;
void dfs(int u, int p){
    for(auto v : graph[u]){
        if(v != p){
            dfs(v,u);
            st[u] += st[v];
        }
    }
    cnt += st[u];
}
int bfs(int start){
    queue<int> q; q.push(start);
    vector<int> dist(N+1,-1),par(N+1,-1); dist[start] = 0;
    int maxd = -1, ret = 0;
    while(!q.empty()){
        int u = q.front(); q.pop();
        for(auto v : adj[u]){
            if(dist[v] == -1){
                dist[v] = dist[u]+1;
                par[v] = u;
                q.push(v);
            }
        }
    }
    for(int i = 1;i<=N;++i) graph[i].clear();
    for(int i = 1;i<=N;++i){
        if(dist[i] == -1) return -1;
        graph[par[i]].push_back(i);
    }
    st = vector<int>(N+1,1); cnt = 0;
    dfs(start,0);
    return cnt;
}
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> N;
    for(int i = 1;i<=N;++i){
        int k; cin >> k;
        for(int j = 0;j<k;++j){
            int v; cin >> v;
            adj[v].push_back(i);
        }
    }
    int res = -1, root = -1;
    for(int i = 1;i<=N;++i){
        int ret = bfs(i);
        if(ret == -1) continue;
        if(ret < res || res == -1){
            res = ret;
            root = i;
        }
    }
    cout << res << "\n";
    return 0;
}

Compilation message (stderr)

bosses.cpp: In function 'int bfs(int)':
bosses.cpp:19:9: warning: unused variable 'maxd' [-Wunused-variable]
   19 |     int maxd = -1, ret = 0;
      |         ^~~~
bosses.cpp:19:20: warning: unused variable 'ret' [-Wunused-variable]
   19 |     int maxd = -1, ret = 0;
      |                    ^~~
bosses.cpp: In function 'int main()':
bosses.cpp:50:19: warning: variable 'root' set but not used [-Wunused-but-set-variable]
   50 |     int res = -1, root = -1;
      |                   ^~~~

• Subtask 1: 22 / 22
• Subtask 2: 45 / 45
• Subtask 3: 33 / 33