463. Island Perimeter

Question 1

Can you set up variables adjacentSides and landCount?

Answer 1

let adjacentSides = 0, landCount = 0;

Question 2

Can you loop through grid array?

Answer 2

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {

    }
}

Question 3

In the looping, can you set up variable points to current cell?

Answer 3

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
}
}

Question 4

In the looping, can you set up variable points to the top of the current cell?

Answer 4

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
let top = i > 0 ? grid[i - 1][j] : undefined;
}
}

Question 5

In the looping, can you set up variable points to the left of the current cell?

Answer 5

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
let top = i > 0 ? grid[i - 1][j] : undefined;
let left = j > 0 ? grid[i][j - 1] : undefined;
}
}

Question 6

When current cell value is 1, can you increase the landCount?

Answer 6

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
let top = i > 0 ? grid[i - 1][j] : undefined;
let left = j > 0 ? grid[i][j - 1] : undefined;
if (curr === 1) {
landCount++;
}
}
}

Question 7

When current cell value is 1 and left cell value is 1, can you increase the adjacentSides?

Answer 7

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
let top = i > 0 ? grid[i - 1][j] : undefined;
let left = j > 0 ? grid[i][j - 1] : undefined;
if (curr === 1) {
landCount++;
if (left === 1) conSides++;
}
}
}

Question 8

When current cell value is 1 and top cell value is 1, can you increase the adjacentSides?

Answer 8

for (let i = 0; i < grid.length; i++) {
for (let j = 0; j < grid[i].length; j++) {
let curr = grid[i][j;
let top = i > 0 ? grid[i - 1][j] : undefined;
let left = j > 0 ? grid[i][j - 1] : undefined;
if (curr === 1) {
landCount++;
if (left === 1) conSides++;
if (top === 1) conSides++;
}
}
}

Question 9

Can you return the result base on landCount and adjacentSides?

Answer 9

return landCount * 4 - conSides * 2;