Array
Matrix
Simulation
Description
You start at the cell (rStart, cStart)
of an rows x cols
grid facing east. The northwest corner is at the first row and column in the grid, and the southeast corner is at the last row and column.
You will walk in a clockwise spiral shape to visit every position in this grid. Whenever you move outside the grid's boundary, we continue our walk outside the grid (but may return to the grid boundary later.). Eventually, we reach all rows * cols
spaces of the grid.
Return an array of coordinates representing the positions of the grid in the order you visited them .
Example 1:
Input: rows = 1, cols = 4, rStart = 0, cStart = 0
Output: [[0,0],[0,1],[0,2],[0,3]]
Example 2:
Input: rows = 5, cols = 6, rStart = 1, cStart = 4
Output: [[1,4],[1,5],[2,5],[2,4],[2,3],[1,3],[0,3],[0,4],[0,5],[3,5],[3,4],[3,3],[3,2],[2,2],[1,2],[0,2],[4,5],[4,4],[4,3],[4,2],[4,1],[3,1],[2,1],[1,1],[0,1],[4,0],[3,0],[2,0],[1,0],[0,0]]
Constraints:
1 <= rows, cols <= 100
0 <= rStart < rows
0 <= cStart < cols
Solutions
Solution 1
Python3 Java C++ Go TypeScript JavaScript
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18 class Solution :
def spiralMatrixIII (
self , rows : int , cols : int , rStart : int , cStart : int
) -> List [ List [ int ]]:
ans = [[ rStart , cStart ]]
if rows * cols == 1 :
return ans
k = 1
while True :
for dr , dc , dk in [[ 0 , 1 , k ], [ 1 , 0 , k ], [ 0 , - 1 , k + 1 ], [ - 1 , 0 , k + 1 ]]:
for _ in range ( dk ):
rStart += dr
cStart += dc
if 0 <= rStart < rows and 0 <= cStart < cols :
ans . append ([ rStart , cStart ])
if len ( ans ) == rows * cols :
return ans
k += 2
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26 class Solution {
public int [][] spiralMatrixIII ( int rows , int cols , int rStart , int cStart ) {
int cnt = rows * cols ;
int [][] ans = new int [ cnt ][ 2 ] ;
ans [ 0 ] = new int [] { rStart , cStart };
if ( cnt == 1 ) {
return ans ;
}
for ( int k = 1 , idx = 1 ;; k += 2 ) {
int [][] dirs = new int [][] {{ 0 , 1 , k }, { 1 , 0 , k }, { 0 , - 1 , k + 1 }, { - 1 , 0 , k + 1 }};
for ( int [] dir : dirs ) {
int r = dir [ 0 ] , c = dir [ 1 ] , dk = dir [ 2 ] ;
while ( dk -- > 0 ) {
rStart += r ;
cStart += c ;
if ( rStart >= 0 && rStart < rows && cStart >= 0 && cStart < cols ) {
ans [ idx ++] = new int [] { rStart , cStart };
if ( idx == cnt ) {
return ans ;
}
}
}
}
}
}
}
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23 class Solution {
public :
vector < vector < int >> spiralMatrixIII ( int rows , int cols , int rStart , int cStart ) {
int cnt = rows * cols ;
vector < vector < int >> ans ;
ans . push_back ({ rStart , cStart });
if ( cnt == 1 ) return ans ;
for ( int k = 1 ;; k += 2 ) {
vector < vector < int >> dirs = {{ 0 , 1 , k }, { 1 , 0 , k }, { 0 , -1 , k + 1 }, { -1 , 0 , k + 1 }};
for ( auto & dir : dirs ) {
int r = dir [ 0 ], c = dir [ 1 ], dk = dir [ 2 ];
while ( dk -- > 0 ) {
rStart += r ;
cStart += c ;
if ( rStart >= 0 && rStart < rows && cStart >= 0 && cStart < cols ) {
ans . push_back ({ rStart , cStart });
if ( ans . size () == cnt ) return ans ;
}
}
}
}
}
};
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24 func spiralMatrixIII ( rows int , cols int , rStart int , cStart int ) [][] int {
cnt := rows * cols
ans := [][] int {[] int { rStart , cStart }}
if cnt == 1 {
return ans
}
for k := 1 ; ; k += 2 {
dirs := [][] int {{ 0 , 1 , k }, { 1 , 0 , k }, { 0 , - 1 , k + 1 }, { - 1 , 0 , k + 1 }}
for _ , dir := range dirs {
r , c , dk := dir [ 0 ], dir [ 1 ], dir [ 2 ]
for dk > 0 {
rStart += r
cStart += c
if rStart >= 0 && rStart < rows && cStart >= 0 && cStart < cols {
ans = append ( ans , [] int { rStart , cStart })
if len ( ans ) == cnt {
return ans
}
}
dk --
}
}
}
}
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24 function spiralMatrixIII ( rows : number , cols : number , rStart : number , cStart : number ) : number [][] {
// prettier-ignore
const dir = [[ 1 , 0 ],[ 0 , 1 ],[ - 1 , 0 ],[ 0 , - 1 ]]
let [ x , y , i , size ] = [ cStart , rStart , 0 , 0 ];
const ans : number [][] = [[ y , x ]];
const total = rows * cols ;
while ( ans . length < total ) {
if ( i % 2 === 0 ) size ++ ;
for ( let j = 0 ; ans . length < total && j < size ; j ++ ) {
x += dir [ i ][ 0 ];
y += dir [ i ][ 1 ];
if ( 0 <= x && x < cols && 0 <= y && y < rows ) {
ans . push ([ y , x ]);
}
}
i = ( i + 1 ) % 4 ;
}
return ans ;
}
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31 /**
* @param {number} rows
* @param {number} cols
* @param {number} rStart
* @param {number} cStart
* @return {number[][]}
*/
var spiralMatrixIII = function ( rows , cols , rStart , cStart ) {
// prettier-ignore
const dir = [[ 1 , 0 ],[ 0 , 1 ],[ - 1 , 0 ],[ 0 , - 1 ]]
let [ x , y , i , size ] = [ cStart , rStart , 0 , 0 ];
const ans = [[ y , x ]];
const total = rows * cols ;
while ( ans . length < total ) {
if ( i % 2 === 0 ) size ++ ;
for ( let j = 0 ; ans . length < total && j < size ; j ++ ) {
x += dir [ i ][ 0 ];
y += dir [ i ][ 1 ];
if ( 0 <= x && x < cols && 0 <= y && y < rows ) {
ans . push ([ y , x ]);
}
}
i = ( i + 1 ) % 4 ;
}
return ans ;
};