Submission #53969

#	Time	Username	Problem	Language	Result	Execution time	Memory
53969		khsoo01	Linear Garden (IOI08_linear_garden)	C++11	100 / 100	32 ms	5516 KiB

linear_garden

#include<bits/stdc++.h>
using namespace std;

const int N = 1000005;

int n, m, dt[N/2] = {1}, two[N/2] = {1};
char a[N];

int main()
{
	scanf("%d%d%s",&n,&m,a+1);
	for(int i=1;2*i<=n;i++) {
		two[i] = two[i-1] * 2 % m;
	}
	if(n%2) dt[0]++;
	for(int i=1;2*i<=n;i++) {
		dt[i] = (dt[i-1] + two[i-1] + two[i-1 + n%2]) % m;
	}
	int typ = 0, ans = 1;
	for(int i=1;2*i<=n;i++) {
		if(i == 1) {
			if(a[1] == 'P' && a[2] == 'P') {
				ans = (ans + two[(n-2*i)/2] + 2 * dt[n/2-i]) % m;
			}
			if(a[1] == 'P' && a[2] == 'L') {
				ans = (ans + two[(n-2*i)/2] + dt[n/2-i]) % m;
			}
			if(a[1] == 'L' && a[2] == 'P') {
				ans = (ans + two[(n-2*i)/2]) % m;
			}
			if(a[1] == a[2]) typ = 1;
		}
		else if(typ == 1) {
			if(a[2*i] == 'P') {
				ans = (ans + two[(n-2*i)/2]) % m;
			}
		}
		else if(typ == 2) {
			if(a[2*i] == 'L') {
				ans = (ans + two[(n-2*i+1)/2]) % m;
			}
		}
		else if(a[2*i-1] == a[1] && a[2*i] == a[2]) {
			if(a[1] == 'P') {
				ans = (ans + two[(n-2*i+1)/2]) % m;
			}
			else {
				ans = (ans + two[(n-2*i)/2]) % m;
			}
		}
		else {
			if(a[2*i-1] == 'P') {
				if(a[2*i] == 'P') {
					ans = (ans + two[(n-2*i+1)/2] + dt[n/2-i]) % m;
				}
				else {
					ans = (ans + two[(n-2*i)/2] + dt[n/2-i]) % m;
				}
			}
			if(a[2*i-1] == a[2*i]) typ = 1;
			else typ = 2;
		}
	}
	if(typ%2 == 0 && n%2 && a[n] == 'P') {
		ans = (ans + 1) % m;
	}
	printf("%d\n",ans);
}

Compilation message (stderr)

linear_garden.cpp: In function 'int main()':
linear_garden.cpp:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%s",&n,&m,a+1);
  ~~~~~^~~~~~~~~~~~~~~~~~~~

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