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algorithm notes: leetcode#661 image smoother

admin 11月 12, 2020 0

Problem

Solution

Analysis

Python implementation

class :
    def imageSmoother(self, M):
        """
        :type M: List[List[int]]
        :rtype: List[List[int]]
        """
        m, n = len(M), len(M[0])
        result = [[0]*n for _ in range(m)]
        
        for r in range(m):
            for c in range(n):
                count = 0
                for i in range(r-1, r+2):
                    for j in range(c-1, c+2):
                        if 0<=i<m and 0<=j<n:
                            result[r][c] += M[i][j]
                            count +=1
                result[r][c] = result[r][c]//count
        return result

Java implementation

class  {
    public int[][] imageSmoother(int[][] M) {
        int m = M.length;
        int n = M[0].length;
        int[][] result = new int[m][n];
        
        for(int r = 0; r < m; r++){
            for(int c = 0; c < n; c++){
                int count = 0;
                for(int i = r-1; i < r+2; i++){
                    for(int j = c-1; j < c+2; j++){
                        if(i>=0 && i<m && j>=0 && j<n){
                            result[r][c] += M[i][j];
                            count++;
                        }
                    }
                }
                result[r][c] /= count;
            }
        }
        return result;
    }
}

Time complexity

O(mn).

Space complexity

O(mn).

Link

661. Image Smoother
(中文版) 算法笔记: 力扣#661 图片平滑器