Submission #3464820

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Source Code Expand

#include <bits/stdc++.h>

#define For(i, l, r) for(register int i = (l), i##end = (int)(r); i <= i##end; ++i)
#define Fordown(i, r, l) for(register int i = (r), i##end = (int)(l); i >= i##end; --i)
#define Set(a, v) memset(a, v, sizeof(a))
#define Cpy(a, b) memcpy(a, b, sizeof(a))
#define debug(x) cout << #x << ": " << (x) << endl
#define DEBUG(...) fprintf(stderr, __VA_ARGS__)

using namespace std;

template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, 1 : 0; }
template<typename T> inline bool chkmax(T &a, T b) { return b > a ? a = b, 1 : 0; }

inline int read() {
	int x(0), sgn(1); char ch(getchar());
	for (; !isdigit(ch); ch = getchar()) if (ch == '-') sgn = -1;
	for (; isdigit(ch); ch = getchar()) x = (x * 10) + (ch ^ 48);
	return x * sgn;
}

void File() {
	freopen ("F.in", "r", stdin);
	freopen ("F.out", "w", stdout);
}

const int N = 5010, Mod = 1e9 + 7;

int n; char str[N];

inline int fpm(int x, int power) {
	int res = 1;
	for (; power; power >>= 1, x = 1ll * x * x % Mod)
		if (power & 1) res = 1ll * res * x % Mod;
	return res;
}

int dp[N][N];

inline void Add(int &a, int b) {
	if ((a += b) >= Mod) a -= Mod;
}

int main () {

	n = read();
	scanf ("%s", str + 1);

	int len = strlen(str + 1);

	dp[0][0] = 1;
	For (i, 0, n - 1) For (j, 0, i) {
		Add(dp[i + 1][j + 1], dp[i][j] * 2 % Mod);
		Add(dp[i + 1][max(0, j - 1)], dp[i][j]);
	}

	printf ("%d\n", 1ll * dp[n][len] * fpm(fpm(2, len), Mod - 2) % Mod);

	return 0;

}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:57:68: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long long int’ [-Wformat=]
  printf ("%d\n", 1ll * dp[n][len] * fpm(fpm(2, len), Mod - 2) % Mod);
                                                                    ^
./Main.cpp: In function ‘void File()’:
./Main.cpp:23:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
  freopen ("F.in", "r", stdin);
                              ^
./Main.cpp:24:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
  freopen ("F.out", "w", stdout);
                                ^
./Main.cpp: In function ‘int main()’:
./Main.cpp:47:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%s", str + 1);
              ...

Judge Result