Submission #668528

#	Time	Username	Problem	Language	Result	Execution time	Memory
668528		4EVER	Cijanobakterije (COCI21_cijanobakterije)	C++11	70 / 70	41 ms	16696 KiB

Main

/******************************
*    author : @hihihihi       *
*    date : 07 / 11 / 2022    *
******************************/

#include <bits/stdc++.h>
// #pragma GCC optimize("O2")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimize ("O3,unroll-loops,no-stack-protector")
// #pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

// template
#define PB push_back
#define ALL(i_) i_.begin(), i_.end()
#define LOG2(x_) (31 - __builtin_clz(x_))
#define getBit(x_, i_) ((x_ >> i_) & (ll) 1)
#define rd(l_, r_) (l_ + rng() % (r_ - l_ + 1))
#define FOR(i_, a_, b_)  for(int i_ = (int) (a_); i_ <= (int) (b_); ++i_)
#define FORD(i_, a_, b_) for(int i_ = (int) (a_); i_ >= (int) (b_); --i_)
// debugger 
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef DEBUG
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
 
typedef long long ll;
typedef long double ld;

template<class X, class Y> bool minimize(X &x, const Y &y){
    X eps = 1e-9;
    if (x > y + eps) {
        x = y;
        return 1;
    }
    return 0;
}

template<class X, class Y> bool maximize(X &x, const Y &y) {
    X eps = 1e-9;
    if (x + eps < y) {
        x = y;
        return 1;
    }
    return 0;
}

template<class T> T Abs(const T &x) { return (x < 0 ? -x : x); }
template<class T> using heap_min = priority_queue<T, vector<T>, greater<T>>;
template<class T> using heap_max = priority_queue<T>;

const int mod = (int) 1e9 + 7;

template<class X, class Y> void Add(X &x, const Y &y){
    x += y;
    if(x >= mod) x -= mod;
    if(x < 0) x += mod;
}

const int oo = (int) 1e9 + 99;
const array<int, 2> dxy8[] = { {-1, 0}, {1, 0}, {0, 1}, {0, -1}, {1, -1}, {1, 1}, {-1, 1}, {-1, -1} };
const array<int, 2> dxy4[] = { {-1, 0}, {1, 0}, {0, 1}, {0, -1} };

const int maxn = (int) 1e5 + 1;
const int LOG = (int) LOG2(maxn) + 3;

void File(){
    #define TASK "CIJANOBAKTERIJE"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
}

int n, m;
vector<int> adj[maxn];

void ReadInput(){
    cin >> n >> m;
    FOR(i, 1, m){
        int u, v; cin >> u >> v;
        adj[u].PB(v);
        adj[v].PB(u);
    }
}

int cnt;
int vs[maxn], in[maxn], out[maxn];
int child[3][maxn];

void DFS_IN(int u, int par){
    vs[u] = cnt;
    child[1][u] = child[2][u] = (int) -1e7;
    for(int v : adj[u]) if(v != par){
        DFS_IN(v, u);
        maximize(in[u], in[v] + 1);
        if(in[v] + 1 > child[1][u]){
            child[2][u] = child[1][u];
            child[1][u] = in[v] + 1;
        }
        else if(in[v] + 1 > child[2][u]){
            child[2][u] = in[v] + 1;
        }
    }
}

void DFS_OUT(int u, int par){
    if(par != -1){
        out[u] = out[par] + 1;
        if(in[u] + 1 == child[1][par]){
            maximize(out[u], child[2][par] + 1);
        }
        else{
            maximize(out[u], child[1][par] + 1);
        }
    }
    for(int v : adj[u]) if(v != par) DFS_OUT(v, u);
}

int f[maxn];

void Solve(){
    memset(vs, -1, sizeof vs);
    FOR(i, 1, n) if(vs[i] == -1){
        ++cnt;
        DFS_IN(i, -1);
        DFS_OUT(i, -1);
    }
    int res = 0;
    FOR(i, 1, n) maximize(f[vs[i]], max(in[i], out[i]) + 1);
    FOR(i, 1, cnt) res += f[i];
    cout << res;
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    File();
    ReadInput();
    Solve();
    cerr << "\nTime elapsed: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void File()':
Main.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 6 / 6
• Subtask 3: 6 / 6
• Subtask 4: 15 / 15
• Subtask 5: 28 / 28