Submission #71706

#	Time	Username	Problem	Language	Result	Execution time	Memory
71706		the_general (#119)	Cross on the Grid (FXCUP3_cross)	C++98	22 / 100	1074 ms	600 KiB

cross

#include<stdio.h>
#define MOD 1000000007

int a(int);
int b(int);
int c(int);
int d(int);
int n;

int a(int x){
	if(x<3) return 0;
	if(x==3) return 1;
	return (((c(x-2)+d(x-3)-b(x-3))%MOD+b(x-2))%MOD+d(x-3))%MOD;
}

int b(int x){
	if(x<3) return 0;
	if(x==3) return 1;
	return (((c(x-2)+d(x-3)-a(x-3))%MOD+a(x-2))%MOD+d(x-3))%MOD;
}

int c(int x){
	if(x<3) return 0;
	if(x==3) return 1;
	return ((a(x-2)+b(x-2))%MOD+d(x-3))%MOD;
}

int d(int x){
	if(x==1 || x==2) return 1;
	return (((a(x)+b(x))%MOD+c(x))%MOD+d(x-1))%MOD;
}

int main(){
	scanf("%d", &n);
	printf("%d", (d(n))%MOD);
}

Compilation message (stderr)

cross.cpp: In function 'int main()':
cross.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 0 / 35
• Subtask 3: 0 / 43