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refactor 119
1 parent 483e1a5 commit 59bdb74

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+33
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  • src/main/java/com/fishercoder/solutions

1 file changed

+33
-42
lines changed

src/main/java/com/fishercoder/solutions/_119.java

Lines changed: 33 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -3,53 +3,44 @@
33
import java.util.ArrayList;
44
import java.util.List;
55

6-
/**
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* 119. Pascal's Triangle II
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* Given an index k, return the kth row of the Pascal's triangle.
9-
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For example, given k = 3,
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Return [1,3,3,1].
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Note:
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Could you optimize your algorithm to use only O(k) extra space?
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*/
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176
public class _119 {
187

19-
public static class Solution1 {
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public List<Integer> getRow(int rowIndex) {
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if (rowIndex < 0) {
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return new ArrayList();
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}
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List<List<Integer>> result = new ArrayList();
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List<Integer> row = new ArrayList();
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row.add(1);
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result.add(row);
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for (int i = 1; i <= rowIndex; i++) {
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List<Integer> newRow = new ArrayList();
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newRow.add(1);
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List<Integer> lastRow = result.get(i - 1);
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for (int j = 1; j < lastRow.size(); j++) {
33-
newRow.add(lastRow.get(j - 1) + lastRow.get(j));
8+
public static class Solution1 {
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public List<Integer> getRow(int rowIndex) {
10+
if (rowIndex < 0) {
11+
return new ArrayList();
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}
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List<List<Integer>> result = new ArrayList();
14+
List<Integer> row = new ArrayList();
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row.add(1);
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result.add(row);
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for (int i = 1; i <= rowIndex; i++) {
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List<Integer> newRow = new ArrayList();
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newRow.add(1);
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List<Integer> lastRow = result.get(i - 1);
21+
for (int j = 1; j < lastRow.size(); j++) {
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newRow.add(lastRow.get(j - 1) + lastRow.get(j));
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}
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newRow.add(1);
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result.add(newRow);
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}
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return result.get(result.size() - 1);
3428
}
35-
newRow.add(1);
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result.add(newRow);
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}
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return result.get(result.size() - 1);
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}
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}
4130

42-
public static class Solution2 {
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/** O(k) space */
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public List<Integer> getRow(int rowIndex) {
45-
List<Integer> row = new ArrayList<>();
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for (int i = 0; i <= rowIndex; i++) {
47-
row.add(0, 1);
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for (int j = 1; j < row.size() - 1; j++) {
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row.set(j, row.get(j) + row.get(j + 1));
31+
public static class Solution2 {
32+
/**
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* O(k) space
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*/
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public List<Integer> getRow(int rowIndex) {
36+
List<Integer> row = new ArrayList<>();
37+
for (int i = 0; i <= rowIndex; i++) {
38+
row.add(0, 1);
39+
for (int j = 1; j < row.size() - 1; j++) {
40+
row.set(j, row.get(j) + row.get(j + 1));
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}
42+
}
43+
return row;
5044
}
51-
}
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return row;
5345
}
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}
5546
}

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