Submission #70108723

Source Code Expand

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#include <stdio.h>
#include <inttypes.h>
#define MOD_BY 998244353
int mul(int a, int b) {
  return (int)((int64_t)a * b % MOD_BY);
}
int pou(int a, uint64_t b) {
  int r = 1;
  while (b > 0) {
    if (b & 1) r = mul(r, a);
    a = mul(a, a);
    b >>= 1;
  }
  return r;
}
int main(void) {
  uint64_t N;
 
 
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#include <stdio.h>
#include <inttypes.h>

#define MOD_BY 998244353

int mul(int a, int b) {
	return (int)((int64_t)a * b % MOD_BY);
}

int pou(int a, uint64_t b) {
	int r = 1;
	while (b > 0) {
		if (b & 1) r = mul(r, a);
		a = mul(a, a);
		b >>= 1;
	}
	return r;
}

int main(void) {
	uint64_t N;
	if (scanf("%" SCNu64, &N) != 1) return 1;
	printf("%d\n", pou(2, N - 1));
	return 0;
}

/*

P_1：まず適当に決める
P_i (i >= 2)：「それまでの最大値+1」か「それまでの最小値-1」の2択
+n / -n (n > 1) を使ってしまうと、後で中途半端な値しか残らなくなって詰む

*/

Submission Info

Judge Result