Submission #393438

#	Time	Username	Problem	Language	Result	Execution time	Memory
393438		Kenzo_1114	Horses (IOI15_horses)	C++17	17 / 100	541 ms	44284 KiB

horses

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 500010;
const long long int MOD = 1e9 + 7;

int n;
long long int x[MAXN], y[MAXN];
long long int seg[4 * MAXN], lz[4 * MAXN];

void refresh(int pos, int bg, int ed)
{
	if(lz[pos] == 1)	return;

	long long int Lz = lz[pos];	lz[pos] = 1;
	seg[pos] = (seg[pos] * Lz) % MOD;

	if(bg == ed)	return;	

	int mid = (bg + ed) >> 1, l = 2 * pos, r = l + 1;
	lz[l] = (lz[l] * Lz) % MOD;
	lz[r] = (lz[r] * Lz) % MOD;
}

void upd(int pos, int bg, int ed, int p, int q, long long int val)
{
	refresh(pos, bg, ed);
	if(q < p || q < bg || ed < p)	return;
	if(p <= bg && ed <= q)
	{
		lz[pos] = (lz[pos] * val) % MOD;
		refresh(pos, bg, ed);
		return;
	}
	
	int mid = (bg + ed) >> 1, l = 2 * pos, r = l + 1;
	
	upd(l, bg, mid, p, q, val);
	upd(r, mid + 1, ed, p, q, val);

	seg[pos] = max(seg[l], seg[r]);
}

long long int fe(long long int a, long long int p)
{
	if(p == 0)	return 1;
	if(p == 1)	return a;

	long long int b = fe(a, p / 2);
	b = (b * b) % MOD;

	if(p & 1)	b = (b * a) % MOD;
	return b;
}

int updateX(int pos, int val)
{
	pos++;
	upd(1, 1, n, pos, n, fe(x[pos], MOD - 2));
	x[pos] = val;
	upd(1, 1, n, pos, n, x[pos]);

	refresh(1, 1, n);
	return (int) seg[1];
}

int updateY(int pos, int val)
{
	pos++;
	upd(1, 1, n, pos, pos, fe(y[pos], MOD - 2));
	y[pos] = val;
	upd(1, 1, n, pos, pos, y[pos]);

	refresh(1, 1, n);
	return (int) seg[1];
}

int init(int N, int X[], int Y[])
{
	n = N;
	for(int i = n; i > 0; i--)	x[i] = X[i - 1];
	for(int i = n; i > 0; i--)	y[i] = Y[i - 1];

	for(int i = 1; i < 4 * MAXN; i++)	lz[i] = 1, seg[i] = 1;

	for(int i = 1; i <= n; i++) 
	{
		upd(1, 1, n, i, n, x[i]);
		upd(1, 1, n, i, i, y[i]);
	}

	refresh(1, 1, n);
	return (int) seg[1];
}
/*
int N;
long long int X[MAXN], Y[MAXN];

int main ()
{
	scanf("%d", &N);
	for(int i = 0; i < N; i++)	scanf("%lld", &X[i]);
	for(int i = 0; i < N; i++)	scanf("%lld", &Y[i]);

	printf("%d\n", init(N, X, Y));
	printf("%d\n", updateY(1, 2));
}

3
2 1 3 
3 4 1

*/

Compilation message (stderr)

horses.cpp: In function 'void refresh(int, int, int)':
horses.cpp:19:6: warning: unused variable 'mid' [-Wunused-variable]
   19 |  int mid = (bg + ed) >> 1, l = 2 * pos, r = l + 1;
      |      ^~~

• Subtask 1: 17 / 17
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 23
• Subtask 5: 0 / 23