edit 119

Author: fishercoder1534

README.md

@@ -478,7 +478,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |122|[Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_122.java)| O(n)|O(1) | Medium | Greedy
 |121|[Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_121.java)| O(n)|O(1) | Easy| DP
 |120|[Triangle](https://leetcode.com/problems/triangle/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_120.java)| O(m*n)|O(n) | Medium| DP
-|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_119.java)| O(n^2)|O(1) | Easy| 
+|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_119.java)| O(n^2)|O(k) | Easy| 
 |118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_118.java)| O(n^2)|O(1) | Easy| 
 |117|[Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_117.java)| O(n)|O(1) | Medium| BFS
 |116|[Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_116.java)| O(n)|O(1) | Medium| BFS

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

@@ -1,32 +1,51 @@
 package com.fishercoder.solutions;
 import java.util.*;
-/**Given an index k, return the kth row of the Pascal's triangle.
+
+/**
+ * 119. Pascal's Triangle II
+ * Given an index k, return the kth row of the Pascal's triangle.
 
  For example, given k = 3,
  Return [1,3,3,1].
 
  Note:
- Could you optimize your algorithm to use only O(k) extra space?*/
+ Could you optimize your algorithm to use only O(k) extra space?
+ */
 
 public class _119 {
 
-    public List<Integer> getRow(int rowIndex) {
-        if(rowIndex < 0) return new ArrayList();
-        List<List<Integer>> result = new ArrayList();
-        List<Integer> row = new ArrayList();
-        row.add(1);
-        result.add(row);
-        for(int i = 1; i <= rowIndex; i++){
-            List<Integer> newRow = new ArrayList();
-            newRow.add(1);
-            List<Integer> lastRow = result.get(i-1);
-            for(int j = 1; j < lastRow.size(); j++){
-                newRow.add(lastRow.get(j-1) + lastRow.get(j));
+    public static class Solution1 {
+        public List<Integer> getRow(int rowIndex) {
+            if (rowIndex < 0) return new ArrayList();
+            List<List<Integer>> result = new ArrayList();
+            List<Integer> row = new ArrayList();
+            row.add(1);
+            result.add(row);
+            for (int i = 1; i <= rowIndex; i++) {
+                List<Integer> newRow = new ArrayList();
+                newRow.add(1);
+                List<Integer> lastRow = result.get(i - 1);
+                for (int j = 1; j < lastRow.size(); j++) {
+                    newRow.add(lastRow.get(j - 1) + lastRow.get(j));
+                }
+                newRow.add(1);
+                result.add(newRow);
+            }
+            return result.get(result.size() - 1);
+        }
+    }
+
+    public static class Solution_OkSpace {
+        public List<Integer> getRow(int rowIndex) {
+            List<Integer> row = new ArrayList<>();
+            for (int i = 0; i < rowIndex + 1; i++) {
+                row.add(0, 1);
+                for (int j = 1; j < row.size() - 1; j++) {
+                    row.set(j, row.get(j) + row.get(j + 1));
+                }
             }
-            newRow.add(1);
-            result.add(newRow);
+            return row;
         }
-        return result.get(result.size()-1);
     }
 
 }