Submission #2555451

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f(i, x, n) for(int i = x; i < (int)(n); ++i)

int const N = 3000;
int n, md, o[N + 1], ch[N + 1][N + 1], p2[N + 1], p2m[N + 1], dp[N + 1][N + 1];

inline void ad(int &x, int y) { if ((x += y) >= md)x -= md; }
inline void sb(int &x, int y) { if ((x -= y) <  0 )x += md; }

inline int pw(int x, int p){
	int an = 1;
	while (p){
		if (p & 1)an = (ll)an * x % md;
		p >>= 1;
		x = (ll)x * x % md;
	}
	return an;
}

int main(){
	scanf("%d%d", &n, &md);
	assert(n <= 50);
	p2[0] = 1;
	f(i, 1, n + 1)if ((p2[i] = p2[i - 1] << 1) >= md)p2[i] -= md;
	p2m[0] = 1;
	f(i, 1, n + 1)if ((p2m[i] = p2m[i - 1] << 1) >= md - 1)p2m[i] -= md - 1;
	f(i, 0, n + 1){
		ch[i][0] = 1;
		f(j, 1, i + 1)if ((ch[i][j] = ch[i - 1][j] + ch[i - 1][j - 1]) >= md)ch[i][j] -= md;
	}
	dp[1][1] = 1;
	f(i, 2, n + 1)f(j, 1, i + 1)ad(dp[i][j], (ll)dp[i - 1][j] * j % md), ad(dp[i][j], dp[i - 1][j - 1]);
	o[0] = 2;
	f(i, 1, n + 1)f(j, 0, i + 1)j & 1 ? sb(o[i], (ll)ch[i][j] * pw(2, p2m[i - j]) % md) : ad(o[i], (ll)ch[i][j] * pw(2, p2m[i - j]) % md);
	int an = o[n];
	f(i, 1, n + 1)f(a, 0, n - i + 1)f(j, 1, i + 1)i & 1 ? sb(an, (ll)ch[n][i] * ch[n - i][a] % md * o[n - i - a] % md * dp[i][j] % md * pw(p2[j], n - i - a) % md * pw(p2[j] - 1, a) % md) : ad(an, (ll)ch[n][i] * ch[n - i][a] % md * o[n - i - a] % md * dp[i][j] % md * pw(p2[j], n - i - a) % md * pw(p2[j] - 1, a) % md);
	printf("%d\n", an);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:23:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &md);
                        ^

Judge Result