Submission #19559924

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Source Code Expand

#include <stdio.h>

const int Mod = 1000000007;

int main()
{
	int N;
	char S[1000001];
	scanf("%d", &N);
	scanf("%s", S);
	if (N == 1) {
		printf("1\n");
		fflush(stdout);
		return 0;
	}
	
	int i, j, flag;
	long long dp[4] = {};
	
	for (i = 1; S[i] == S[0]; i++);
	if (i == N) {
		printf("1\n");
		fflush(stdout);
		return 0;
	}
	dp[0] = i + 1;
	dp[S[i] - 'A' + 1] = (i + 1) / 2;
	dp[6 - (S[i] - 'A' + 1) - (S[0] - 'A' + 1)] = i / 2;
	if (i % 2 == 0) flag = S[i] - 'A' + 1;
	else flag = 6 - (S[i] - 'A' + 1) - (S[0] - 'A' + 1);
	
	for (i++; i < N; i++) {
		if (S[i] == 'A') {
			dp[1] = dp[0];
			dp[0] = (dp[0] + dp[2] + dp[3] + ((flag != 1)? 1: 0)) % Mod;			
			dp[2] ^= dp[3];
			dp[3] ^= dp[2];
			dp[2] ^= dp[3];
			if (flag == 1) flag = 4;
			else if (flag == 2) flag = 3;
			else if (flag == 3) flag = 2;
			else flag = 1;
		} else if (S[i] == 'B') {
			dp[2] = dp[0];
			dp[0] = (dp[0] + dp[1] + dp[3] + ((flag != 2)? 1: 0)) % Mod;			
			dp[1] ^= dp[3];
			dp[3] ^= dp[1];
			dp[1] ^= dp[3];
			if (flag == 1) flag = 3;
			else if (flag == 2) flag = 4;
			else if (flag == 3) flag = 1;
			else flag = 2;
		} else {
			dp[3] = dp[0];
			dp[0] = (dp[0] + dp[1] + dp[2] + ((flag != 3)? 1: 0)) % Mod;			
			dp[1] ^= dp[2];
			dp[2] ^= dp[1];
			dp[1] ^= dp[2];
			if (flag == 1) flag = 2;
			else if (flag == 2) flag = 1;
			else if (flag == 3) flag = 4;
			else flag = 3;
		}
	}
	printf("%lld\n", dp[0]);
	fflush(stdout);
	return 0;
}

Submission Info

Compile Error

./Main.c: In function ‘main’:
./Main.c:9:2: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
    9 |  scanf("%d", &N);
      |  ^~~~~~~~~~~~~~~
./Main.c:10:2: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
   10 |  scanf("%s", S);
      |  ^~~~~~~~~~~~~~

Judge Result