【LeetCode】566.Reshape the Matrix解题报告

【LeetCode】566.Reshape the Matrix解题报告

tags: Array

题目地址：https://leetcode.com/problems/reshape-the-matrix/#/description
题目描述：

  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.

Example1:

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.

Example2:

Input:
  nums = [[1,2],[3,4]] r = 2, c = 4
Output:
  [[1,2],[3,4]]
Explanation:
  There is no way to reshape a 2 * 2 matrix to a 2 * 4 matrix. So output the original matrix.

Solutions:

public class Solution {    public int[][] matrixReshape(int[][] nums, int r, int c) {        int original_r = nums.length;          int original_c = nums[0].length;          if (original_r * original_c == r * c) {              int[][] result = new int[r][c];              for (int i = 0; i < r * c; i++) {                  result[i / c][i % c] = nums[i / original_c][i % original_c];              }              return result;          } else {              return nums;          }      }}

  本题利用nums.length,它的值就是矩阵的行数，nums[0].length就是列数，后面一个巧妙运用除和求余得到行列数，得解。

Date：2017年5月25日