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Merged
merged 1 commit into from
Jan 25, 2021
Merged

add solution and test case for 79 #150

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41 changes: 41 additions & 0 deletions src/main/java/com/fishercoder/solutions/_79.java
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Original file line number Diff line number Diff line change
Expand Up @@ -40,4 +40,45 @@ boolean search(char[][] board, String word, int i, int j, int pos) {
return false;
}
}

// O(1) space solution
public static class Solution2 {
public boolean exist(char[][] board, String word) {

// do DFS traversal
int row = board.length;
int col = board[0].length;

for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
if (board[i][j] == word.charAt(0) && search(board, i, j, word, 0) == true)
return true;
}
}
return false;
}

private boolean search(char[][] board, int i, int j, String word, int index) {
if (index == word.length() - 1)
return true;

// store the visited char in temp variable
char temp = board[i][j];
board[i][j] = ' ';
if (i > 0 && board[i - 1][j] == word.charAt(index + 1) && search(board, i - 1, j, word, index + 1) == true)
return true;
if (i < board.length - 1 && board[i + 1][j] == word.charAt(index + 1) && search(board, i + 1, j, word, index + 1) == true)
return true;

if (j > 0 && board[i][j - 1] == word.charAt(index + 1) && search(board, i, j - 1, word, index + 1) == true)
return true;


if (j < board[0].length - 1 && board[i][j + 1] == word.charAt(index + 1) && search(board, i, j + 1, word, index + 1) == true)
return true;

board[i][j] = temp;
return false;
}
}
}
13 changes: 13 additions & 0 deletions src/test/java/com/fishercoder/_79Test.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,11 +8,14 @@

public class _79Test {
private static _79.Solution1 solution1;
private static _79.Solution2 solution2;
private static char[][] board;

@BeforeClass
public static void setup() {

solution1 = new _79.Solution1();
solution2 = new _79.Solution2();
}

@Test
Expand Down Expand Up @@ -48,4 +51,14 @@ public void test3() {
assertEquals(false, solution1.exist(board, "aaa"));
}

@Test
public void test4() {
board = new char[][]{
{'A', 'B', 'H', 'I'},
{'K', 'E', 'H', 'S'},
{'A', 'D', 'E', 'E'},
};
assertEquals(true, solution2.exist(board, "ABHISHEK"));
}

}