feat: add solutions to leetcode problem: No.0118

See https://leetcode-cn.com/problems/pascals-triangle

Author: yanglbme

solution/0100-0199/0118.Pascal's Triangle/README.md

@@ -27,22 +27,54 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
+先设置每一行首尾元素为 1，其它元素为 0。然后根据杨辉三角，设置每一行其它元素即可。
+
 <!-- tabs:start -->
 
 ### **Python3**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def generate(self, numRows: int) -> List[List[int]]:
+        if numRows == 0:
+            return []
+        res = []
+        for i in range(numRows):
+            t = [1 if j == 0 or j == i else 0 for j in range(i + 1)]
+            for j in range(1, i):
+                t[j] = res[i - 1][j - 1] + res[i - 1][j]
+            res.append(t)
+        return res
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public List<List<Integer>> generate(int numRows) {
+        List<List<Integer>> res = new ArrayList<>();
+        if (numRows == 0) return res;
+        for (int i = 0; i < numRows; ++i) {
+            // 每一行
+            List<Integer> t = new ArrayList<>();
+            for (int j = 0; j < i + 1; ++j) {
+                boolean firstOrLast = j == 0 || j == i;
+                // 设置每一行首尾元素为1，其它元素为0
+                t.add(firstOrLast ? 1 : 0);
+            }
+            for (int j = 1; j < i; ++j) {
+                int val = res.get(i - 1).get(j - 1) + res.get(i - 1).get(j);
+                t.set(j, val);
+            }
+            res.add(t);
+        }
+        return res;
+    }
+}
 ```
 
 ### **...**

solution/0100-0199/0118.Pascal's Triangle/README_EN.md

@@ -41,13 +41,43 @@
 ### **Python3**
 
 ```python
-
+class Solution:
+    def generate(self, numRows: int) -> List[List[int]]:
+        if numRows == 0:
+            return []
+        res = []
+        for i in range(numRows):
+            t = [1 if j == 0 or j == i else 0 for j in range(i + 1)]
+            for j in range(1, i):
+                t[j] = res[i - 1][j - 1] + res[i - 1][j]
+            res.append(t)
+        return res
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public List<List<Integer>> generate(int numRows) {
+        List<List<Integer>> res = new ArrayList<>();
+        if (numRows == 0) return res;
+        for (int i = 0; i < numRows; ++i) {
+            // 每一行
+            List<Integer> t = new ArrayList<>();
+            for (int j = 0; j < i + 1; ++j) {
+                boolean firstOrLast = j == 0 || j == i;
+                // 设置每一行首尾元素为1，其它元素为0
+                t.add(firstOrLast ? 1 : 0);
+            }
+            for (int j = 1; j < i; ++j) {
+                int val = res.get(i - 1).get(j - 1) + res.get(i - 1).get(j);
+                t.set(j, val);
+            }
+            res.add(t);
+        }
+        return res;
+    }
+}
 ```
 
 ### **...**

solution/0100-0199/0118.Pascal's Triangle/Solution.java

@@ -1,17 +1,21 @@
 class Solution {
     public List<List<Integer>> generate(int numRows) {
-        List<List<Integer>> re = new ArrayList<>();
-        if (numRows == 0) return re;
-        re.add(Collections.singletonList(1));
-        for (int i = 1; i < numRows; i++) {
-            List<Integer> list = new ArrayList<>();
-            re.add(list);
-            for (int j = 0; j < i + 1; j++) {
-                int l = j - 1 < 0 ? 0 : re.get(i - 1).get(j - 1);
-                int r = j > i - 1 ? 0 : re.get(i - 1).get(j);
-                list.add(l + r);
+        List<List<Integer>> res = new ArrayList<>();
+        if (numRows == 0) return res;
+        for (int i = 0; i < numRows; ++i) {
+            // 每一行
+            List<Integer> t = new ArrayList<>();
+            for (int j = 0; j < i + 1; ++j) {
+                boolean firstOrLast = j == 0 || j == i;
+                // 设置每一行首尾元素为1，其它元素为0
+                t.add(firstOrLast ? 1 : 0);
             }
+            for (int j = 1; j < i; ++j) {
+                int val = res.get(i - 1).get(j - 1) + res.get(i - 1).get(j);
+                t.set(j, val);
+            }
+            res.add(t);
         }
-        return re;
+        return res;
     }
 }

solution/0100-0199/0118.Pascal's Triangle/Solution.py

@@ -1,18 +1,11 @@
 class Solution:
     def generate(self, numRows: int) -> List[List[int]]:
-        res = [[1], [1, 1]]
         if numRows == 0:
             return []
-        elif numRows == 1:
-            return [res[0]]
-
-        # from the 3. row on 
-        for i in range(2, numRows):
-            counter = 1
-            temp = [1, 1]
-            # should add len(res[i - 1]) - 1 elements in to temp
-            for j in range(len(res[i - 1]) - 1):
-                temp.insert(counter, res[i - 1][j] + res[i - 1][j + 1])
-                counter += 1
-            res.append(temp)
+        res = []
+        for i in range(numRows):
+            t = [1 if j == 0 or j == i else 0 for j in range(i + 1)]
+            for j in range(1, i):
+                t[j] = res[i - 1][j - 1] + res[i - 1][j]
+            res.append(t)
         return res