Submission #559838

#	Time	Username	Problem	Language	Result	Execution time	Memory
559838		fatemetmhr	Mousetrap (CEOI17_mousetrap)	C++17	0 / 100	282 ms	67472 KiB

mousetrap

// Be name khoda //
 
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
 
#define all(x)   x.begin(), x.end()
#define fi       first
#define se       second
#define pb       push_back
 
const int maxn5 = 1e6 + 10;
const int maxnt = 5e6 + 10;
const int inf   = 1e9;
 
int tale, mo, dp[maxn5], id[maxn5], newid = 0;
int htotale[maxn5], st[maxn5], parr[maxn5];
int valu[maxn5], valval[maxn5], zz[maxn5];
int cmp[maxn5];
vector <int> adj[maxn5], ver;
vector <pair<int, int>> av;
pair <int, int> mx[maxnt];
int mn[maxnt], lazy[maxnt], lazy2[maxnt];
 
inline bool dfs(int v, int par){
    if(v == tale){
        dp[v] = 0;
        htotale[v] = 0;
        return true;
    }
    int mx = 0, smx = 0;
    int z = -1;
    for(auto u : adj[v]) if(u != par){
        bool re = dfs(u, v);
        if(re){
            z = u;
        }
        if(dp[u] >= mx){
            smx = mx;
            mx = dp[u];
        }
        else
            smx = max(smx, dp[u]);
    }
    if(z == -1){
        dp[v] = smx + int(adj[v].size()) - 1;
        //cout << "false " << v << ' ' << dp[v] << endl;
        return false;
    }
 
    htotale[v] = htotale[z] + int(adj[v].size()) - 2 + (v == mo);
    ver.pb(v);
    parr[v] = par;
    zz[v] = z;
 
    //ft[ver.size()] = newid;
 
    return true;
}
 
 
inline bool ok(int v){
    for(int i = v; i <= ver.size(); i++){
        valval[i]--;
        if(valval[i] < 0)
            return false;
    }
    return true;
}
 
int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
 
    int n, a, b; cin >> n >> a >> b;
    a--; b--;
    mo = b;
    tale = a;
    for(int i = 0; i < n - 1; i++){
        int a, b; cin >> a >> b;
        a--; b--;
        adj[a].pb(b);
        adj[b].pb(a);
    }
 
    //assert(a != b);
 
    if(a == b)
        return cout << 0 << endl, 0;
 
    dfs(mo, -1);
 
    reverse(all(ver)); // az m be t hast
    //assert(ver.size() == 1);
 
    int mxx = 0, smx = 0;
    int pos = 1;
    for(auto v : ver){
        for(auto u : adj[v]) if(u != parr[v] && u != zz[v]){
            cmp[newid] = pos;
            valu[newid++] = dp[u] + htotale[v];
            cout << v << ' ' << u << ' ' << dp[u] << ' ' << htotale[v] << endl;
            if(mxx <= dp[u] + htotale[v]){
                smx = mxx;
                mxx = dp[u] + htotale[v];
            }
            else
                smx = max(smx, dp[u] + htotale[v]);
            //cout << "aha " << v << ' ' << u << ' ' << dp[u] << ' ' << htotale[v] << endl;
        }
        st[pos] = newid;
        pos++;
    }
 
    //return cout << min(inf, smx) << endl, 0;
 
    
    //build(0, newid, 1);
    for(int i = 1; i <= ver.size(); i++)
        valval[i] = i;
    //build2(0, ver.size() + 1, 1);
 
    int done = 0;
    int ans = inf;
    //assert(st[pos - 1] == newid);
    //cout << newid << endl;
    if(newid == 0){
        return cout << 0 << endl, 0;
    }
    while(done < newid){
        int z = -1;
        for(int i = 0; i < newid; i++) if(z == -1 || valu[i] >= valu[z])
            z = i;
        //assert(done <= 1);
        ans = min(ans, valu[z] + done);
        //if(done == 1)
            //assert(mx[1].fi + done == smx);
        //if(done == 0)
            //assert(mx[1].fi == mxx);
        if(ok(cmp[z])){
            done++;
            for(int i = 0; i < st[cmp[z]]; i++)
                valu[i]--;
            valu[z] = -inf;
        }
        else
            break;
    }
    if(done == newid)
        ans = min(ans, done);
    //assert(done == 1);
    cout << ans << endl;
}

Compilation message (stderr)

mousetrap.cpp: In function 'bool ok(int)':
mousetrap.cpp:65:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |     for(int i = v; i <= ver.size(); i++){
      |                    ~~^~~~~~~~~~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:120:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |     for(int i = 1; i <= ver.size(); i++)
      |                    ~~^~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 25
• Subtask 3: 0 / 20
• Subtask 4: 0 / 35