1198. Find Smallest Common Element in All Rows

SmallestCommonElement.cs

public class Solution {
  public int SmallestCommonElement(int[][] mat) {
    var cursors = new int[mat.Length];
    var ROWS = mat.Length;
    var COLS = mat[0].Length;
    while(true){
      var row = 0;
      var allFound = true;
      var min = -1;
      while(row + 1 < ROWS){
        while(mat[row + 1][cursors[row + 1]] < mat[row][cursors[row]]){
          if(cursors[row + 1] + 1 >= COLS)
            return -1;
          cursors[row + 1]++;
        }
        
        min = mat[row][cursors[row]];
        
        if(mat[row][cursors[row]] == mat[row + 1][cursors[row + 1]]){
          row++;
          continue;
        }
        allFound = false;
        break;
      }
      if(allFound)
        return min;
      while(row >= 0){
        cursors[row]++;
        if(cursors[row] == COLS)
          return -1;
        row--;
      }      
    }
    return -1;
    
  }
}