fork download
copy 
  1. #include <iostream>
  2. #include <cstring>
  3. #include <algorithm>
  4. using namespace std;
  5.  
  6. const int INF = 1e9;
  7. int n;
  8. int a[22][22]; // 初始矩阵
  9.  
  10. int main() {
  11.     cin >> n;
  12.     for (int i = 1; i <= n; i++) {
  13.         string s;
  14.         cin >> s;
  15.         for (int j = 1; j <= n; j++) {
  16.             a[i][j] = s[j-1] - '0';
  17.         }
  18.     }
  19.     int ans = INF;
  20.     int total_masks = 1 << n;
  21.     // 用于存储行的数组，多出两个边界元素（索引0和n+1）方便处理
  22.     int prev_row[22], curr_row[22], next_row[22];
  23.     for (int mask = 0; mask < total_masks; mask++) {
  24.         // 初始化prev_row全0
  25.         memset(prev_row, 0, sizeof(prev_row));
  26.         // 设置curr_row为mask对应的第一行操作
  27.         memset(curr_row, 0, sizeof(curr_row));
  28.         for (int j = 1; j <= n; j++) {
  29.             curr_row[j] = (mask >> (j-1)) & 1;
  30.         }
  31.         int total_ops = __builtin_popcount(mask); // 第一行的操作次数
  32.         // 逐行确定剩余行的操作
  33.         for (int i = 1; i < n; i++) {
  34.             // 计算下一行操作
  35.             memset(next_row, 0, sizeof(next_row));
  36.             for (int j = 1; j <= n; j++) {
  37.                 next_row[j] = a[i][j] ^ curr_row[j] ^ prev_row[j] ^ curr_row[j-1] ^ curr_row[j+1];
  38.             }
  39.             // 累加下一行的操作次数
  40.             for (int j = 1; j <= n; j++) {
  41.                 total_ops += next_row[j];
  42.             }
  43.             // 更新行：当前行变为上一行，下一行变为当前行
  44.             memcpy(prev_row, curr_row, sizeof(curr_row));
  45.             memcpy(curr_row, next_row, sizeof(next_row));
  46.         }
  47.         // 验证最后一行是否满足全0条件
  48.         bool ok = true;
  49.         for (int j = 1; j <= n; j++) {
  50.             int val = curr_row[j] ^ prev_row[j] ^ curr_row[j-1] ^ curr_row[j+1];
  51.             if (val != a[n][j]) {
  52.                 ok = false;
  53.                 break;
  54.             }
  55.         }
  56.         if (ok) {
  57.             ans = min(ans, total_ops);
  58.         }
  59.     }
  60.     if (ans == INF) {
  61.         cout << -1 << endl;
  62.     } else {
  63.         cout << ans << endl;
  64.     }
  65.     return 0;
  66. }
Success #stdin #stdout 0s 5280KB
comments (?)
stdin
copy 
3
1 1 1
1 1 1
1 1 1
stdout
copy 
-1
https://ideone.com/34wZ7F
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!