README_EN.md

1260. Shift 2D Grid

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Description

Given a 2D grid of size m x n and an integer k. You need to shift the grid k times.

In one shift operation:

• Element at grid[i][j] moves to grid[i][j + 1].
• Element at grid[i][n - 1] moves to grid[i + 1][0].
• Element at grid[m - 1][n - 1] moves to grid[0][0].

Return the 2D grid after applying shift operation k times.

 

Example 1:

Input: grid = [[1,2,3],[4,5,6],[7,8,9]], k = 1
Output: [[9,1,2],[3,4,5],[6,7,8]]

Example 2:

Input: grid = [[3,8,1,9],[19,7,2,5],[4,6,11,10],[12,0,21,13]], k = 4
Output: [[12,0,21,13],[3,8,1,9],[19,7,2,5],[4,6,11,10]]

Example 3:

Input: grid = [[1,2,3],[4,5,6],[7,8,9]], k = 9
Output: [[1,2,3],[4,5,6],[7,8,9]]

 

Constraints:

• m == grid.length
• n == grid[i].length
• 1 <= m <= 50
• 1 <= n <= 50
• -1000 <= grid[i][j] <= 1000
• 0 <= k <= 100

Solutions

Python3

class Solution:
    def shiftGrid(self, grid: List[List[int]], k: int) -> List[List[int]]:
        m, n = len(grid), len(grid[0])
        k %= (m * n)
        t = [grid[i][j] for i in range(m) for j in range(n)]
        t = t[-k:] + t[:-k]
        for i in range(m):
            for j in range(n):
                grid[i][j] = t[i * n + j]
        return grid

Java

class Solution {
    public List<List<Integer>> shiftGrid(int[][] grid, int k) {
        int m = grid.length, n = grid[0].length;
        k %= (m * n);
        List<List<Integer>> ans = new ArrayList<>();
        for (int i = 0; i < m; ++i) {
            List<Integer> t = new ArrayList<>();
            for (int j = 0; j < n; ++j) {
                t.add(0);
            }
            ans.add(t);
        }
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                int t = (i * n + j + k) % (m * n);
                ans.get(t / n).set(t % n, grid[i][j]);
            }
        }
        return ans;
    }
}

C++

class Solution {
public:
    vector<vector<int>> shiftGrid(vector<vector<int>>& grid, int k) {
        int m = grid.size(), n = grid[0].size();
        vector<vector<int>> ans(m, vector<int>(n));
        for (int i = 0; i < m; ++i)
        {
            for (int j = 0; j < n; ++j)
            {
                int t = (i * n + j + k) % (m * n);
                ans[t / n][t % n] = grid[i][j];
            }
        }
        return ans;
    }
};

Go

func shiftGrid(grid [][]int, k int) [][]int {
	m, n := len(grid), len(grid[0])
	ans := make([][]int, m)
	for i := range ans {
		ans[i] = make([]int, n)
	}
	for i := 0; i < m; i++ {
		for j := 0; j < n; j++ {
			t := (i*n + j + k) % (m * n)
			ans[t/n][t%n] = grid[i][j]
		}
	}
	return ans
}

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