packageeasy;

importjava.util.*;

publicclassPascalsTriangle {

publicstaticList<List<Integer>>generate(intnumRows) {

List<List<Integer>>result =newArrayList();

if(numRows <1)returnresult;

List<Integer>row =newArrayList();

row.add(1);

result.add(row);

for(inti =1;i <numRows;i++){

List<Integer>newRow =newArrayList();

newRow.add(1);

List<Integer>lastRow =result.get(i-1);

for(intj =1;j <lastRow.size();j++){

newRow.add(lastRow.get(j-1) +lastRow.get(j));

}

newRow.add(1);

result.add(newRow);

}

returnresult;

}

publicstaticvoidmain(String...strings){

intnumRows =2;

generate(numRows);

}

}

|125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)|[Solution](../../blob/master/EASY/src/easy/ValidPalindrome.java)| O(n)|O(1) | Easy| Two Pointers

|122|[Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/)|[Solution](../../blob/master/MEDIUM/src/medium/BestTimeToBuyAndSellStockII.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](../../blob/master/EASY/src/easy/BestTimeToBuyAndSellStock.java)| O(n)|O(1) | Easy| DP

|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/)|[Solution](../../blob/master/EASY/src/easy/PascalsTriangle.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](../../blob/master/HARD/src/hard/PopulatingNextRightPointersinEachNodeII.java)| O(n)|O(1) | Hard| BFS

|116|[Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/)|[Solution](../../blob/master/MEDIUM/src/medium/PopulatingNextRightPointersinEachNode.java)| O(n)|O(1) | Medium| BFS

|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/)|[Solution](../../blob/master/EASY/src/easy/MinimumDepthofBinaryTree.java)| O(n)|O(1)~O(h) | Easy| BFS, DFS