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Commit06be5bd

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solves number of islands in java
1 parent97f179c commit06be5bd

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2 files changed

+53
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2 files changed

+53
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‎README.md

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| 191|[Number of One Bits](https://leetcode.com/problems/number-of-1-bits)|[![Java](assets/java.png)](src/NumberOf1Bit.java)[![Python](assets/python.png)](python/number_of_1_bits.py)||
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| 198|[House Robber](https://leetcode.com/problems/house-robber)|[![Java](assets/java.png)](src/HouseRobber.java)[![Python](assets/python.png)](python/house_robber.py)||
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| 199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view)|[![Java](assets/java.png)](src/BinaryTreeRightSideView.java)||
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| 200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|||
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| 200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|[![Java](assets/java.png)](src/NumberOfIslands.java)||
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| 201|[Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range)|||
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| 202|[Happy Number](https://leetcode.com/problems/happy-number)|[![Java](assets/java.png)](src/HappyNumber.java)[![Python](assets/python.png)](python/happy_number.py)||
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| 203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements)|[![Java](assets/java.png)](src/RemoveLinkedListElements.java)[![Python](assets/python.png)](python/remove_linked_list_elements.py)||

‎src/NumberOfIslands.java

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// https://leetcode.com/problems/number-of-islands
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// T: O(m * n)
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// T: O(m * n)
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publicclassNumberOfIslands {
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privatestaticfinalcharVISITED ='0';
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privatestaticfinalcharISLAND ='1';
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publicintnumIslands(char[][]grid) {
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finalintrows =grid.length,columns =grid[0].length;
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intislands =0;
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for (introw =0 ;row <rows ;row++) {
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for (intcolumn =0 ;column <columns ;column++) {
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if (isIsland(grid[row][column])) {
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islands++;
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markIslandAsSeen(grid,row,column);
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}
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}
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}
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returnislands;
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}
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privatebooleanisIsland(charc) {
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returnc ==ISLAND;
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}
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privatevoidmarkIslandAsSeen(char[][]grid,introw,intcolumn) {
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if (!isValidPosition(grid,row,column) || !isIsland(grid[row][column]))return;
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markVisited(grid,row,column);
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markIslandAsSeen(grid,row -1,column);
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markIslandAsSeen(grid,row,column +1);
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markIslandAsSeen(grid,row +1,column);
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markIslandAsSeen(grid,row,column -1);
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}
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privatebooleanisValidPosition(char[][]grid,introw,intcolumn) {
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returnrow >=0
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&&row <grid.length
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&&column >=0
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&&column <grid[0].length;
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}
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privatebooleanalreadyVisited(charc) {
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returnc ==VISITED;
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}
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privatevoidmarkVisited(char[][]grid,introw,intcolumn) {
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grid[row][column] =VISITED;
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}
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}

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