# 305. Number of Islands II

{%hackmd theme-dark %}

CIT country infructure team

west -> east

x, y = CIT.build()

MxN
2x3
day1:
(2,0)
day2:
(2,0)
day5
(2,2)

MxN 3x5
row1:
row2
row3: 5

time: t, M x N grid
TC: O(tmn)

--
[ [*0, 1, 0^]
L [*0, 0, 0^]] R

check find(L) == find(R)
[ [0, 1, 2]
[0, 0, 0]]
[ [1, 1, 0]
[0, 1, 0]]
[ [1, 1, 0]
[0, 1, 1]]

----

L [ [L, 1, R] R
[L, 4, R]]

int whenToFinish(int m, int n, CIT &cit) {
    
    for (int t = 0; ; t++) {
        auto &[x, y] = cit.build();
        
    }
    1
2   5   4
    3

[1 2 3 6 7 8]

[1 2 3] [1 2] [2 3] [1] [2] [3] => sum
[6 7 8 ] ... => sum

[1 2 3 4] => 10
[2 3 4] => 10 -1
###### tags: `mock interview` `面試`