洛谷 P5441 【XR-2】伤痕

思路

奇怪的构造思路……
讲不懂，看原题解吧，洛谷题解
顺便 % 一波 xht。

代码

/*
  Name: P5441 【XR-2】伤痕 
  Author: Loceaner
  Date: 08/09/20 17:40
  Description:
  Debug:
*/
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const int A = 1e5 + 11;
const int B = 1e6 + 11;
const int mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;

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

int n, a[A];

int main() {
  n = read();
  if (n == 1) return cout << "0\n0\n", 0;
  cout << n * (n - 3) * (n * n + 6 * n - 31) / 48 << '\n';
  int m = (n + 1) >> 1;
  for (int i = 1; i <= n; i++) {
    memset(a, 0, sizeof(a));
    for (int j = 1; j <= m; j++) a[(i + j - 1) % n + 1] = 1;
    for (int j = 1; j <= n; j++) cout << a[j] << " ";
    puts("");
  }
  return 0;
}