Submission #3812402

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <algorithm>
#define MOD 1000000007

int n, m;
int p[111111];

int br[4][4] = {1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1};
int tr[4][4] = {1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 2};

struct Matrix{
	int A[4][4];
	void clear(){memset(A, 0, sizeof(A));}
	void init(){for(int i = 0; i < 4; i++) A[i][i] = 1;}
	Matrix operator* (const Matrix a)const{
		static Matrix tmp;
		tmp.clear();
		for(int i = 0; i < 4; i++)
			for(int k = 0; k < 4; k++)
				for(int j = 0; j < 4; j++)
					tmp.A[i][j] = (tmp.A[i][j] + 1ll * A[i][k] * a.A[k][j]) % MOD;
		return tmp;
	}
}ts, tb, Ans;

Matrix Pow(Matrix a, int b){
	static Matrix tm;
	tm.clear(), tm.init();
	for(; b; b >>= 1, a = a * a)
		if(b & 1) tm = tm * a;
	return tm;
}

int main(){
	scanf("%d %d", &n, &m);
	memcpy(ts.A, tr, sizeof(tr));
	memcpy(tb.A, br, sizeof(br));
	for(int i = 1; i <= m; i++) scanf("%d", &p[i]);
	p[++m] = n;
	Ans.A[0][0] = 1;
	int ls = 0;
	
	for(int i = 1; i <= m; i++){
		Ans = Ans * Pow(ts, p[i] - ls);
		if(i != m) Ans = Ans * tb;
		ls = p[i] + 1;
	}
	
	printf("%d\n", Ans.A[0][3]);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:36:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
                        ^
./Main.cpp:39:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for(int i = 1; i <= m; i++) scanf("%d", &p[i]);
                                                ^

Judge Result