Submission #686118

#	Time	Username	Problem	Language	Result	Execution time	Memory
686118		pragmatist	Mountain Trek Route (IZhO12_route)	C++17	0 / 100	2 ms	340 KiB

route

/*
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("O3")
#pragma GCC target ("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
*/

#include<bits/stdc++.h>
 
#define ld long double
#define sz(v) (int)v.size()
#define ll long long
#define pb push_back
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define nl "\n"

using namespace std;

const int N = (int)1e6 + 7; // make sure this is right
const int M = (int)1e6 + 7;
const int inf = (int)2e9 + 7;
const ll INF = (ll)3e18 + 7; 
const ll MOD = (ll)998244353; // make sure this is right

bool bit(int x, int i) {
	return x >> i & 1;
}

int sum(int x, int y) {
	x += y;
	if(x >= MOD) x -= MOD;
	return x;
}

int mult(int x, int y) {
	return 1ll * x * y % MOD;
}

int n, k, a[N];
int sz[N], p[N];
pair<int, int> l[N], r[N];

int get(int v) {
	return (v == p[v] ? v : p[v] = get(p[v]));
}

void comb(int u, int v) {
	u = get(u);
	v = get(v);
	if(u == v) return;
	l[v] = min(l[v], l[u]);
	r[v] = max(r[v], r[u]);
	p[u] = v;
	sz[v] += sz[u];
}

void solve() {
	cin >> n >> k;
	int mx = 0;
	for(int i = 1; i <= n; ++i) {
		cin >> a[i];
	}
	for(int i = 1; i <= n; ++i) {
		p[i] = l[i].x = r[i].x = i;
		if(i == 1) l[i].y = n;
		else l[i].y = i - 1;

		if(i == n) r[i].y = 1;
		else r[i].y = i + 1;
		sz[i] = 1;
	}
	for(int i = 1; i <= n; ++i) {
		if(a[i] == a[r[i].y]) {
			comb(i, r[i].y);
		}
	}
	set<pair<int, int> > s;
	for(int i = 1; i <= n; ++i) {
	    int x = get(i);
		s.insert({sz[x], x});	
	}

	ll ans = 0;
	while(!s.empty()) {
		int x = s.begin() -> y;
		s.erase(s.begin());
		
		if(sz[x] == n) break;
		int L = get(l[x].y), R = get(r[x].y);
		
		if(a[x] < a[L] && a[x] < a[R]) {
			int can = min(k / sz[x], min(a[L], a[R]) - a[x]);
			ans += 2 * can;
			k -= can * sz[x];
			a[x] += can;
		    if(can == 0) continue;

		    if(a[x] == a[L]) comb(L, x);
			if(a[x] == a[R]) comb(R, x);
			
			x = get(x);
			s.insert({sz[x], x});
		}
	}
	cout << ans << "\n";
}
	
signed main() {	
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	freopen("in.txt", "r", stdin);
	int test = 1;
	//cin >> test;
	for(int i = 1; i <= test; ++i) {
	 	//cout << "Case #" << i << ": ";
		solve();
	}
	return 0;
}

Compilation message (stderr)

route.cpp: In function 'void solve()':
route.cpp:64:6: warning: unused variable 'mx' [-Wunused-variable]
   64 |  int mx = 0;
      |      ^~
route.cpp: In function 'int main()':
route.cpp:116:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |  freopen("in.txt", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100