Game of Life LeetCode solution in C++

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// Idea: Encode the value into 2-bit value, the first bit is the value of next
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// state, and the second bit is the value of current state
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class Solution {
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 public:
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  void gameOfLife(vector<vector<int>> &board) {
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    int m = board.size();
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    int n = board[0].size();
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    for (int i = 0; i < m; ++i) {
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      for (int j = 0; j < n; ++j) {
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        encode(board, i, j);
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      }
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    }
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    for (int i = 0; i < m; ++i) {
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      for (int j = 0; j < n; ++j) {
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        board[i][j] >>= 1;
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      }
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    }
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  }
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  void encode(vector<vector<int>> &board, int row, int col) {
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    int ones = 0;
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    int zeros = 0;
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    int m = board.size();
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    int n = board[0].size();
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    int cur = board[row][col];
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    if (row >= 1 && col >= 1) {
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      ones += (board[row - 1][col - 1] & 1);
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      zeros += !(board[row - 1][col - 1] & 1);
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    }
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    if (row >= 1) {
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      ones += (board[row - 1][col] & 1);
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      zeros += !(board[row - 1][col] & 1);
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    }
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    if (row >= 1 && col < n - 1) {
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      ones += (board[row - 1][col + 1] & 1);
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      zeros += !(board[row - 1][col + 1] & 1);
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    }
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    if (col < n - 1) {
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      ones += (board[row][col + 1] & 1);
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      zeros += !(board[row][col + 1] & 1);
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    }
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    if (row < m - 1 && col < n - 1) {
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      ones += (board[row + 1][col + 1] & 1);
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      zeros += !(board[row + 1][col + 1] & 1);
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    }
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    if (row < m - 1) {
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      ones += (board[row + 1][col] & 1);
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      zeros += !(board[row + 1][col] & 1);
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    }
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    if (row < m - 1 && col >= 1) {
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      ones += (board[row + 1][col - 1] & 1);
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      zeros += !(board[row + 1][col - 1] & 1);
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    }
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    if (col >= 1) {
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      ones += (board[row][col - 1] & 1);
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      zeros += !(board[row][col - 1] & 1);
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    }
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    if (ones < 2 && cur == 1) {
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      cur += 0 << 1;
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    } else if (ones >= 2 && ones <= 3 && cur == 1) {
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      cur += 1 << 1;
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    } else if (ones > 3 && cur == 1) {
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      cur += 0 << 1;
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    } else if (ones == 3 && cur == 0) {
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      cur += 1 << 1;
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    } else {
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      cur += cur << 1;
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    }
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    board[row][col] = cur;
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  }
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};