103.水流问题

direction = [[1,0],[0,1],[-1,0],[0,-1]]
first = set()
second = set()

def dfs(grap,x,y,visit,num):
    if visit[x][y]:
        return 
    visit[x][y] = True
    num.add((x,y))
    for i,j in direction:
        curx = x+i 
        cury = y+j
        if 0<=curx<len(grap) and 0<=cury<len(grap[0]) and grap[curx][cury]>=grap[x][y]:
            dfs(grap,curx,cury,visit,num)

def main():
    global first
    global second

    n,m = map(int,input().split())
    grap = []
    for i in range(n):
        grap.append(list(map(int,input().split())))

    visit = [[False]*m for _ in range(n)]
    for i in range(n):
        dfs(grap,i,0,visit,first)
    for i in range(m):
        dfs(grap,0,i,visit,first)

    visit = [[False]*m for i in range(n)]
    for i in range(n):
        dfs(grap,i,m-1,visit,second)
    for j in range(m):
        dfs(grap,n-1,j,visit,second)

    res = first & second # 不能写成  first and second
    for i ,j in res:
        print(f"{i} {j}")

if __name__=='__main__':
    main()

103. 水流问题