566. Reshape the Matrix

public class Solution {
    public int[][] matrixReshape(int[][] nums, int r, int c) {
        ArrayList<Integer> li=new ArrayList<Integer>();
        int i=0,j=0,count=0;
        if((nums.length*nums[0].length)!=(r*c))return nums;
        for(;i<nums.length;i++){
            for(j=0;j<nums[0].length;j++){
                li.add(nums[i][j]);
            }
        }
        int[][] res=new int[r][c];
    
        for(i=0;i<r;i++){
            for(j=0;j<c;j++){
                res[i][j]=li.get(count++);
            }
        }
        return res;
    }
}

太蠢了，人家只用一次循环就搞定了。

public class Solution {
    public int[][] matrixReshape(int[][] nums, int r, int c) {
      
        int row = nums.length;
        int col = nums[0].length;
        int [][] result = new int[r][c];
        
        if (r*c!=row*col){
            return nums;
        }
        int n=0, m=0;
        for (int i=0; i<row; i++){
            for (int j=0; j<col; j++){
                result[n][m]=nums[i][j];
                m++;
                    
                if (m==c){
                    m=0;
                    n++;
                }
                
              }
        }
            
        return result;
        }
   
    }