Find a Peak Element II LeetCode solution in C++

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class Solution {
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 public:
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  int maxEl(vector<vector<int>> &mat, int n, int m, int col) {
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    int maxi = -1;
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    int ind = -1;
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    for (int i = 0; i < n; i++) {
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      if (mat[i][col] > maxi) {
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        maxi = mat[i][col];
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        ind = i;
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      }
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    }
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    return ind;
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  }
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  vector<int> findPeakGrid(vector<vector<int>> &mat) {
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    int n = mat.size();
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    int m = mat[0].size();
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    int low = 0;
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    int high = m - 1;
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    while (low <= high) {
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      int mid = (low + high) / 2;
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      int row = maxEl(mat, n, m, mid);
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      int left = mid - 1 >= 0 ? mat[row][mid - 1] : -1;
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      int right = mid + 1 < m ? mat[row][mid + 1] : -1;
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      if (mat[row][mid] > left && mat[row][mid] > right)
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        return {row, mid};
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      else if (mat[row][mid] < left)
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        high = mid - 1;
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      else
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        low = mid + 1;
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    }
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    return {-1, -1};
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  }
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};