golang 解法, 执行用时: 72 ms, 内存消耗: 7 MB, 提交时间: 2020-10-30 16:08:35

func islandPerimeter(grid [][]int) int {
    circle := 0
    for i, row := range grid {
        for j, b := range row {
            if b == 1 {
                circle += 4
                if j > 0 && row[j-1] == 1 {
                    circle -= 2
                }
                if i > 0 && grid[i-1][j] == 1 {
                    circle -= 2
                }
            }
        }
    }
    return circle
}

python3 解法, 执行用时: 136 ms, 内存消耗: 13.7 MB, 提交时间: 2020-10-30 16:04:15

class Solution:
    def islandPerimeter(self, grid: List[List[int]]) -> int:
        # 遍历数组, 有相邻的1, 则-2
        circle = 0
        for i,row in enumerate(grid):
            for j,b in enumerate(row):
                if b == 1:
                    circle += 4
                    if j > 0 and row[j-1] == 1:
                        circle -= 2
                    if i > 0 and grid[i-1][j] == 1:
                        circle -= 2
        return circle