Submission #71371833

Source Code Expand

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#include <stdio.h>
#define MOD_BY 998244353
int add(int a, int b) {
  return a + b - MOD_BY * (a + b >= MOD_BY);
}
int sub(int a, int b) {
  return b == 0 ? a : add(a, MOD_BY - b);
}
int mul(int a, int b) {
  return (int)((long long)a * b % MOD_BY);
}
int pou(int a, int b) {
  int r = 1;
  while (b > 0) {
    if (b & 1) r = mul(r, a);
    a = mul(a, a);
 
 
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#include <stdio.h>

#define MOD_BY 998244353

int add(int a, int b) {
	return a + b - MOD_BY * (a + b >= MOD_BY);
}

int sub(int a, int b) {
	return b == 0 ? a : add(a, MOD_BY - b);
}

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

int pou(int a, int 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) {
	int N;
	if (scanf("%d", &N) != 1) return 1;
	printf("%d\n", N <= 1 ? 0 : sub(pou(2, N), add(N, 1)));
	return 0;
}

/*

実験してOEIS

1234 / / /
342 / 1 / /
24 / 13 / /
4 / 132 / /
43 / 2 / 1 /
4 / 23 / 1 /
43 / / 12 /
4 / 3 / 12 /
42 / 3 / / 1
4 / 32 / / 1
43 / / 2 / 1
4 / 3 / 2 / 1

// JavaScript
function calc(n) {
  const retu = ["*".repeat(n)];
  for (let i = 1; i < n; i++) retu.push("");
  let cnt = 0;
  while (retu.some((s) => s.length !== 1)) {
    for (let i = 0; i < n; i++) {
      if (retu[i].length >= 2) {
        retu[0] += retu[i].charAt(0);
        retu[i + 1] += retu[i].charAt(1);
        retu[i] = retu[i].substring(2);
        break;
      }
    }
    cnt++;
  }
  return cnt;
}

→ https://oeis.org/A000295

function calc2(n) {
  return (1 << n) - (n + 1);
}

*/

Submission Info

Judge Result