# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
363617 | silverfish | Friend (IOI14_friend) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "friend.h"
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+1;
vector<int> adj[N];
long long dp[N][2];
int vis[N], d[N];
void dfs(int u, int p, int *conf){
for(int v : adj[u]){
if(v != p) dfs(v, u, conf);
}
for(int v : adj[u]){
if(v != p){
dp[u][0] += max(dp[v][1], dp[v][0]);
dp[u][1] += dp[v][0];
}
}
dp[u][1] += 1LL*conf[u];
}
int findSample(int n, int conf[],int host[],int protocol[]){
bool subtask2 = 1, subtask3 = 1, subtask4 = 1, subtask5 = 1;
for(int i = 1; i < n; ++i){
if(protocol[i] != 1) subtask2 = 0;
if(protocol[i] != 2) subtask3 = 0;
if(protocol[i] != 0) subtask4 = 0;
if(conf[i] != 1) subtask5 = 0;
}
if(subtask2){
long long ans = 0;
for(int i = 0; i < n; ++i) ans += 1LL*conf[i];
return ans;
}
if(subtask3){
return *max_element(conf, conf+n);
}
if(subtask4){
//build tree
for(int i = 1; i < n; ++i){
adj[host[i]].push_back(i);
adj[i].push_back(host[i]);
}
dfs(0, 0, conf);
return max(dp[0][1], dp[0][0]);
}
if(subtask5){
for(int i = 1; i < n; ++i){
if(protocol[i] == 0){
adj[host[i]].push_back(i);
adj[i].push_back(host[i]);
}else{
for(int j : adj[host[i]]){
adj[i].push_back(j);
adj[j].push_back(i);
}
}
}
memset(vis, 0, sizeof vis);
int ans = 0;
for(int i = 0; i < n; ++i){
if(vis[i]) continue;
assert(!vis[i]);
array<int,2> curans = {0LL, 0LL};
queue<int> q;
q.push(i);
d[i] = 0;
vis[i] = 1;
// node, depth
while(q.size()){
int u = q.front(); q.pop();
++curans[(d[u]%2)];
for(int v : adj[u]){
if(!vis[v]){
vis[v] = 1;
d[v] = d[u]+1;
q.push(v);
}else(vis[v]){
assert(d[v]%2 != d[u]%2);
}
}
}
assert(q.empty());
assert(max(curans[0], curans[1]) > 0);
ans += max(curans[0], curans[1]);
}
return ans;
}
return -1;
}