岛屿数量
这道题要求在有1，0 组成的m x n的矩阵中找到由1组成的岛屿数量。使用深度或者广度优先算法来进行解题。
深度：
def solution(matrix):m,n = len(matrix),len(matrix[0])res = 0def dfs(x,y):if 0<=x<m and 0<=y<n and matrix[x][y] == 1:matrix[x][y] = 0dfs(x+1,y)dfs(x-1,y)dfs(x,y+1)dfs(x,y-1)for i in range(m):for j in range(n):if matrix[i][j] == 1:res += 1dfs(i,j)return res广度：
def solution(matrix):m,n = len(matrix),len(matrix[0])res = 0def bfs(x,y):q = deque([])q.append((x,y))while q:x1,y1 = q.popleft()if 0<=x1<m and 0<=y1<n and matrix[x1][y1] == 1:matrix[x1][y1] = 0q.append((x1+1,y1))q.append((x1-1,y1))q.append((x1,y1+1))q.append((x1,y1-1))for i in range(m):for j in range(n):if matrix[i][j] == 1:res += 1bfs(i,j)return res岛屿的最大面积
这题与上题类似，只不过他要问最大的陆地的面积是多少。
from collections import deque
def solution(matrix):m,n = len(matrix),len(matrix[0])res = 0def bfs(x,y):area = 0q = deque([])q.append((x,y))while q:x1,y1 = q.popleft()if 0<=x1<m and 0<=y1<n and matrix[x1][y1] == 1:area += 1matrix[x1][y1] = 0q.append((x1+1,y1))q.append((x1-1,y1))q.append((x1,y1+1))q.append((x1,y1-1))return areafor i in range(m):for j in range(n):if matrix[i][j] == 1:res = max(res,bfs(i,j))return res
