Solve Leetcode

- 118. Pascal's Triangle.

Author: abrar-mahedavi

LeetCode/Easy/Pascal's Triangle/README.md

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+`118` `Easy`
+
+# Pascal's Triangle
+
+Given an integer numRows, return the first numRows of Pascal's triangle.
+
+In Pascal's triangle, each number is the sum of the two numbers directly above it as shown:
+
+!["Pascal Triangle"](img.gif "Pascal Triangle")
+
+## Example
+
+```
+Input: numRows = 5
+Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
+```
+
+## Example
+
+```
+Input: numRows = 1
+Output: [[1]]
+```
+
+## Constraints:
+
+- 1 <= numRows <= 30

LeetCode/Easy/Pascal's Triangle/Solution.java

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+class Solution {
+  public List<List<Integer>> generate(int numRows) {
+    List<List<Integer>> answer = new ArrayList<List<Integer>>();
+    List<Integer> row, pre= null;
+    for(int i =0;i<numRows;i++){
+      row = new ArrayList<Integer>();
+      for(int j=0;j<=i;j++){
+        if(j==0 || j==i){
+          row.add(1);
+        }else{
+          // System.out.println(Arrays.toString(pre.toArray()));
+          row.add(pre.get(j-1)+pre.get(j));
+        }
+      }
+      pre = row;
+      answer.add(row);
+    }
+    return answer;
+  }
+}

LeetCode/Easy/Pascal's Triangle/img.gif

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+# AlgoCademy
+
+## Easy
+
+
+- 136 Single Number
+- 344 Reverse String
+- 20  Valid Parentheses
+- 118 Pascal's Triangle
+
+## Medium
+- 73 Set Matrix Zero