Submission #115785

#	Time	Username	Problem	Language	Result	Execution time	Memory
115785		WhipppedCream	Seats (IOI18_seats)	C++17	0 / 100	377 ms	130500 KiB

seats

#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include "seats.h"
using namespace std;
#define X first
#define Y second
#define pb push_back
typedef pair<int, int> ii;
typedef long long ll;

const int maxn = 1e6+5;

int n, m;

int r[maxn];

struct node
{
	int val, cnt, lz;
	node(int a = 0, int b = 0) : val(a), cnt(b)
	{
		lz = 0;
	}
};

node st[4*maxn];

node pull(node &x, node &y)
{
	if(x.val< y.val) return x;
	if(x.val> y.val) return y;
	return node(x.val, x.cnt+y.cnt);
}

void pushdown(int p, int L, int R)
{
	if(st[p].lz == 0) return;
	st[p].val += st[p].lz;
	if(L != R)
	{
		st[2*p].lz += st[p].lz;
		st[2*p+1].lz += st[p].lz;
	}
	st[p].lz = 0;
}

void build(int p = 1, int L = 0, int R = n-1)
{
	if(L == R)
	{
		st[p] = node(0, 1);
		return;
	}
	int M = (L+R)/2;
	build(2*p, L, M);
	build(2*p+1, M+1, R);
	st[p] = pull(st[2*p], st[2*p+1]);
}

void update(int i, int j, int dx, int p = 1, int L = 0, int R = n-1)
{
	pushdown(p, L, R);
	if(i> j || i> R || j< L) return;
	if(i<= L && R<= j) 
	{
		st[p].lz += dx;
		pushdown(p, L, R);
		return;
	}
	int M = (L+R)/2;
	update(i, j, dx, 2*p, L, M);
	update(i, j, dx, 2*p+1, M+1, R);
	st[p] = pull(st[2*p], st[2*p+1]);
}

node ask(int i, int j, int p = 1, int L = 0, int R = n-1)
{
	if(i> R || j< L) return node(1e9, 0);
	pushdown(p, L, R);
	if(i<= L && R<= j) return st[p];
	int M = (L+R)/2;
	node x = ask(i, j, 2*p, L, M);
	node y = ask(i, j, 2*p+1, M+1, R);
	return pull(x, y);
}

int tim[maxn];
int tog[maxn];

void give_initial_chart(int H, int W, vector<int> R, vector<int> C)
{
	m = H;
	n = W;
	assert(m == 1);
	for(int i = 0; i< n; i++)
	{
		tim[i] = C[i];
		tog[C[i]] = i;
	}
	int prv = 0;
	build();
	for(int i = 0; i< n; i++)
	{
		int dat = tim[i];
		int y = 0;
		if(dat && tim[tog[dat-1]]< i) y++;
		if(dat+1< n && tim[tog[dat+1]]< i) y++;  
		int cur = prv + 2 - 2*y;
		update(i, i, cur);
		prv = cur;
	}
	node kk = ask(0, n-1);
	// printf("%d %d\n", kk.val, kk.cnt);
}

void add(int val, int a, int b)
{
	// printf("add %d to [%d %d]\n", val, a, b);
	int m1 = val?tog[val-1]:1e9;
	int m2 = val+1< n?tog[val+1]:1e9;
	// printf("%d %d\n", m1, m2);
	if(m1> m2) swap(m1, m2);
	update(a, min(m1-1, b), 2); 
	// printf("[%d %d] +2\n", a, min(m1-1, b));
	update(max(a, m2), b, -2); 
	// printf("[%d %d] -2\n", max(a, m2), b);
}

void rem(int val, int a, int b)
{
	// printf("remove %d from [%d %d]\n", val, a, b);
	int m1 = val?tog[val-1]:1e9;
	int m2 = val+1< n?tog[val+1]:1e9;
	// printf("%d %d\n", m1, m2);
	if(m1> m2) swap(m1, m2);
	update(a, min(m1-1, b), -2); 
	// printf("[%d %d] -2\n", a, min(m1-1, b));
	update(max(a, m2), b, 2); 
	// printf("[%d %d] +2\n", max(a, m2), b);
}

int swap_seats(int a, int b)
{
	if(a> b) swap(a, b);
	rem(tim[a], a, b-1);
	swap(tog[tim[a]], tog[tim[b]]);
	add(tim[b], a, b-1);
	swap(tim[a], tim[b]);
	// printf("tog = ");
	// for(int i = 0; i< n; i++) printf("%d ", tog[i]);
	// printf("\ntim = ");
	// for(int i = 0; i< n; i++) printf("%d ", tim[i]);
	// printf("\nf   = ");
	// for(int i = 0; i< n; i++) printf("%d ", ask(i, i).val);
	// printf("\n");
	node kk = ask(0, n-1);
	if(kk.val == 2) return kk.cnt;
	return 0;
}

Compilation message (stderr)

seats.cpp: In function 'void give_initial_chart(int, int, std::vector<int>, std::vector<int>)':
seats.cpp:113:7: warning: variable 'kk' set but not used [-Wunused-but-set-variable]
  node kk = ask(0, n-1);
       ^~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 6
• Subtask 3: 0 / 20
• Subtask 4: 0 / 6
• Subtask 5: 0 / 33
• Subtask 6: 0 / 30