結果

問題 No.2677 Minmax Independent Set
ユーザー shobonvip
提出日時 2024-03-15 22:20:59
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 262 ms / 2,000 ms
コード長 2,440 bytes
コンパイル時間 4,379 ms
コンパイル使用メモリ 253,760 KB
最終ジャッジ日時 2025-02-20 05:26:21
ジャッジサーバーID
(参考情報)
judge2 / judge1
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 61
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include<bits/stdc++.h>
using namespace std;
//* ATCODER
#include<atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
//*/
/* BOOST MULTIPRECISION
#include<boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
//*/
typedef long long ll;
#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
template <typename T> bool chmin(T &a, const T &b) {
if (a <= b) return false;
a = b;
return true;
}
template <typename T> bool chmax(T &a, const T &b) {
if (a >= b) return false;
a = b;
return true;
}
template <typename T> T max(vector<T> &a){
assert(!a.empty());
T ret = a[0];
for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
return ret;
}
template <typename T> T min(vector<T> &a){
assert(!a.empty());
T ret = a[0];
for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
return ret;
}
template <typename T> T sum(vector<T> &a){
T ret = 0;
for (int i=0; i<(int)a.size(); i++) ret += a[i];
return ret;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n; cin >> n;
vector ikeru(n, vector<int>(0));
rep(i,0,n-1){
int u, v; cin >> u >> v;
u--; v--;
ikeru[u].push_back(v);
ikeru[v].push_back(u);
}
vector<int> dp0(n);
vector<int> dp1(n);
auto dfs1 = [&](auto self, int i, int p) -> void {
dp0[i] = 0;
dp1[i] = 1;
for (int j: ikeru[i]){
if (j == p) continue;
self(self, j, i);
dp0[i] += max(dp1[j], dp0[j]);
dp1[i] += dp0[j];
}
return;
};
dfs1(dfs1, 0, -1);
vector<int> ans(n);
auto dfs2 = [&](auto self, int i, int p, int up0, int up1) -> void {
vector<int> rui_left0 = {0};
vector<int> rui_left1 = {0};
int now_left0 = 0;
int now_left1 = 0;
int cnt = 0;
for (int j: ikeru[i]){
if (j == p) continue;
now_left0 += max(dp0[j], dp1[j]);
now_left1 += dp0[j];
cnt++;
rui_left0.push_back(now_left0);
rui_left1.push_back(now_left1);
}
reverse(ikeru[i].begin(), ikeru[i].end());
now_left0 = 0;
now_left1 = 0;
for (int j: ikeru[i]){
if (j == p) continue;
cnt--;
self(self, j, i,
max(up0, up1) + rui_left0[cnt] + now_left0,
up0 + rui_left1[cnt] + now_left1 + 1
);
now_left0 += max(dp0[j], dp1[j]);
now_left1 += dp0[j];
}
ans[i] = now_left1 + up0 + 1;
};
dfs2(dfs2, 0, -1, 0, 0);
/*
rep(i,0,n){
cout << ans[i] << ' ';
}cout << '\n';
*/
cout << min(ans) << '\n';
}
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