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feat: add solutions to lc problem: No.2257 #3798

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Merged
yanglbme merged 4 commits into doocs:main from rain84:feature/lc-2257
Nov 22, 2024
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111 changes: 111 additions & 0 deletions solution/2200-2299/2257.Count Unguarded Cells in the Grid/README.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,117 @@ function countUnguarded(m: number, n: number, guards: number[][], walls: number[
}
```

#### JavaScript

```js
function countUnguarded(m, n, guards, walls) {
const g = Array.from({ length: m }, () => Array.from({ length: n }, () => 0));
for (const [i, j] of guards) {
g[i][j] = 2;
}
for (const [i, j] of walls) {
g[i][j] = 2;
}
const dirs = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; ++k) {
let [x, y] = [i, j];
let [a, b] = [dirs[k], dirs[k + 1]];
while (x + a >= 0 && x + a < m && y + b >= 0 && y + b < n && g[x + a][y + b] < 2) {
x += a;
y += b;
g[x][y] = 1;
}
}
}
let ans = 0;
for (const row of g) {
for (const v of row) {
ans += v === 0 ? 1 : 0;
}
}
return ans;
}
```

<!-- tabs:end -->

<!-- solution:end -->

<!-- solution:start -->

### 方法二:DFS + 模拟

<!-- tabs:start -->

#### TypeScript

```ts
function countUnguarded(m: number, n: number, guards: number[][], walls: number[][]): number {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i: number, j: number, dx: number, dy: number) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
```

#### JavaScript

```js
function countUnguarded(m, n, guards, walls) {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i, j, dx, dy) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
```

<!-- tabs:end -->

<!-- solution:end -->
Expand Down
111 changes: 111 additions & 0 deletions solution/2200-2299/2257.Count Unguarded Cells in the Grid/README_EN.md
View file Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -242,6 +242,117 @@ function countUnguarded(m: number, n: number, guards: number[][], walls: number[
}
```

#### JavaScript

```js
function countUnguarded(m, n, guards, walls) {
const g = Array.from({ length: m }, () => Array.from({ length: n }, () => 0));
for (const [i, j] of guards) {
g[i][j] = 2;
}
for (const [i, j] of walls) {
g[i][j] = 2;
}
const dirs = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; ++k) {
let [x, y] = [i, j];
let [a, b] = [dirs[k], dirs[k + 1]];
while (x + a >= 0 && x + a < m && y + b >= 0 && y + b < n && g[x + a][y + b] < 2) {
x += a;
y += b;
g[x][y] = 1;
}
}
}
let ans = 0;
for (const row of g) {
for (const v of row) {
ans += v === 0 ? 1 : 0;
}
}
return ans;
}
```

<!-- tabs:end -->

<!-- solution:end -->

<!-- solution:start -->

### Solution 2: DFS + Simulation

<!-- tabs:start -->

#### TypeScript

```ts
function countUnguarded(m: number, n: number, guards: number[][], walls: number[][]): number {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i: number, j: number, dx: number, dy: number) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
```

#### JavaScript

```js
function countUnguarded(m, n, guards, walls) {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i, j, dx, dy) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
```

<!-- tabs:end -->

<!-- solution:end -->
Expand Down
View file Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
function countUnguarded(m, n, guards, walls) {
const g = Array.from({ length: m }, () => Array.from({ length: n }, () => 0));
for (const [i, j] of guards) {
g[i][j] = 2;
}
for (const [i, j] of walls) {
g[i][j] = 2;
}
const dirs = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; ++k) {
let [x, y] = [i, j];
let [a, b] = [dirs[k], dirs[k + 1]];
while (x + a >= 0 && x + a < m && y + b >= 0 && y + b < n && g[x + a][y + b] < 2) {
x += a;
y += b;
g[x][y] = 1;
}
}
}
let ans = 0;
for (const row of g) {
for (const v of row) {
ans += v === 0 ? 1 : 0;
}
}
return ans;
}
View file Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
function countUnguarded(m, n, guards, walls) {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i, j, dx, dy) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
View file Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
function countUnguarded(m: number, n: number, guards: number[][], walls: number[][]): number {
let c = 0;
const mtx = Array.from({ length: m }, () => Array(n).fill(0));
for (const [i, j] of guards) mtx[i][j] = 2;
for (const [i, j] of walls) mtx[i][j] = 2;

const dfs = (i: number, j: number, dx: number, dy: number) => {
[i, j] = [i + dx, j + dy];

if (i < 0 || m <= i || j < 0 || n <= j || mtx[i][j] === 2) return;

if (mtx[i][j] === 0) {
mtx[i][j] = 1;
c++;
}

dfs(i, j, dx, dy);
};

const DIRS = [-1, 0, 1, 0, -1];
for (const [i, j] of guards) {
for (let k = 0; k < 4; k++) {
const [dx, dy] = [DIRS[k], DIRS[k + 1]];
dfs(i, j, dx, dy);
}
}

return m * n - guards.length - walls.length - c;
}
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