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  1. #include <iostream>
  2. #include <vector>
  3. #include <algorithm>
  4. #include <random>
  5. #include <numeric>
  6.  
  7. using namespace std;
  8.  
  9. void generateBingoCard(int rows = 3) {
  10.     const int cols = 9;
  11.     const int numsPerRow = 5;
  12.     mt19937 engine(random_device{}()); // Shared random engine
  13.  
  14.     // 1. Initialize Column Pools
  15.     vector<vector<int>> colPool(cols);
  16.     for (int j = 0; j < cols; j++) {
  17.         int start = (j * 10) + 1;
  18.         int end = (j == 8) ? 90 : (j + 1) * 10;
  19.         for (int v = start; v <= end; v++) colPool[j].push_back(v);
  20.         shuffle(colPool[j].begin(), colPool[j].end(), engine);
  21.     }
  22.  
  23.     vector<vector<int>> card(rows, vector<int>(cols, 0));
  24.     vector<int> colCount(cols, 0);
  25.     vector<int> rowCount(rows, 0);
  26.  
  27.     // 2. Pass 1: Every column must have at least one number
  28.     for (int j = 0; j < cols; j++) {
  29.         int r = j % rows; 
  30.         card[r][j] = colPool[j].back();
  31.         colPool[j].pop_back();
  32.         colCount[j]++;
  33.         rowCount[r]++;
  34.     }
  35.  
  36.     // 3. Pass 2: Fill remaining slots row-by-row (Unbiased)
  37.     for (int i = 0; i < rows; i++) {
  38.         // Create a list of column indices [0, 1, ..., 8] using a for loop
  39.         vector<int> colOrder(cols);
  40.         for (int k = 0; k < cols; k++) {
  41.             colOrder[k] = k;
  42.         }
  43.  
  44.         // Shuffle the order we look at columns for THIS specific row
  45.         shuffle(colOrder.begin(), colOrder.end(), engine);
  46.  
  47.         for (int j : colOrder) {
  48.             // Stop if the row already has 5 numbers
  49.             if (rowCount[i] >= numsPerRow) break;
  50.  
  51.             // Only fill if cell is empty
  52.             if (card[i][j] == 0) {
  53.                 card[i][j] = colPool[j].back();
  54.                 colPool[j].pop_back();
  55.                 colCount[j]++;
  56.                 rowCount[i]++;
  57.             }
  58.         }
  59.     }
  60.  
  61.     // 4. In-place Vertical Sort (preserves 0/nil positions)
  62.     for (int j = 0; j < cols; j++) {
  63.         for (int pass = 0; pass < rows - 1; pass++) {
  64.             for (int i = 0; i < rows - 1; i++) {
  65.                 if (card[i][j] > 0 && card[i+1][j] > 0 && card[i][j] > card[i+1][j]) {
  66.                     swap(card[i][j], card[i+1][j]);
  67.                 }
  68.             }
  69.         }
  70.     }
  71.  
  72.     // Output formatted like the sample
  73.     for (int i = 0; i < rows; i++) {
  74.         cout << "[";
  75.         for (int j = 0; j < cols; j++) {
  76.             printf("%2d%s", card[i][j], (j == cols - 1 ? "" : ", "));
  77.         }
  78.         cout << "]" << (i == rows - 1 ? "," : "") << endl;
  79.     }
  80. }
  81.  
  82. int main() {
  83.     generateBingoCard(3);
  84.     return 0;
  85. }
Success #stdin #stdout 0.01s 5304KB
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stdin
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Standard input is empty
stdout
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[ 1,  0, 25, 39,  0,  0, 61,  0, 83]
[ 3, 19,  0,  0, 41,  0, 64, 73,  0]
[ 0,  0, 23,  0, 45, 51, 67,  0, 87],
https://ideone.com/Y2YatC
language:
C++ (gcc 8.3)
created:
11 hours ago
visibility:
public

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