/**
 * @author Chaos
 * 566. Reshape the Matrix
 *
 * In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into
 * a new one with different size but keep its original data.
 * You're given a matrix represented by a two-dimensional array, and two positive integers r
 * and c representing the row number and column number of the wanted reshaped matrix, respectively.
 * The reshaped matrix need to be filled with all the elements of the original matrix in the same
 * row-traversing order as they were.
 * If the 'reshape' operation with given parameters is possible and legal, output the new reshaped
 * matrix; Otherwise, output the original matrix.
 *
 * Example:
 *
 * Input:
 * nums =
 *     [[1,2],
 *     [3,4]]
 *  r = 1, c = 4
 *  Output:
 *  [[1,2,3,4]]
 *  Explanation:
 *  The row-traversing of nums is [1,2,3,4]. The new reshaped matrix is a 1 * 4 matrix, fill it row
 *  by row by using the previous list.
 *
 *
 */


class Solution {
    public int[][] matrixReshape(int[][] nums, int r, int c) {
        if (nums == null) return nums;

        int a = nums.length;
        int b = nums[0].length;

        if (a*b!=r*c) return nums;
        int[][] result = new int[r][c];
        int x=0;
        int y=0;
        for(int i=0; i<a;i++){      // notice there I make a mistake here use r, c instead of a, b
            for(int j=0; j<b;j++){  // should be careful which matrix is actually your mean to loop
                if(x>=c){
                    y++;
                    x=0;
                }
                result[y][x++]=nums[i][j];
            }
        }
        return result;
    }

}