feat: add the solution of Pascal's Triangle(118) with kotlin.

Author: relish-wang

README.md

@@ -55,7 +55,7 @@
 | [110][110-question] | [Balanced Binary Tree][110-tips]                             | [✅][110-java] |              | [✅][110-kotlin] |
 | [111][111-question] | [Minimum Depth of Binary Tree][111-tips]                     | [✅][111-java] |              | [✅][111-kotlin] |
 | [112][112-question] | [Path Sum][112-tips]                                         | [✅][112-java] |              | [✅][112-kotlin] |
-| [118][118-question] | [Pascal's Triangle][118-tips]                                | [✅][118-java] |              |                  |
+| [118][118-question] | [Pascal's Triangle][118-tips]                                | [✅][118-java] |              | [✅][118-kotlin] |
 | [119][119-question] | [Pascal's Triangle II][119-tips]                             | [✅][119-java] |              |                  |
 | [121][121-question] | [Best Time to Buy and Sell Stock][121-tips]                  | [✅][121-java] |              |                  |
 | [122][122-question] | [Best Time to Buy and Sell Stock II][122-tips]               | [✅][122-java] |              |                  |
@@ -509,4 +509,5 @@
 [110-kotlin]: ./src/_110/kotlin/Solution.kt
 [111-kotlin]: ./src/_111/kotlin/Solution.kt
 [112-kotlin]: ./src/_112/kotlin/Solution.kt
+[118-kotlin]: ./src/_118/kotlin/Solution.kt
 [771-kotlin]: ./src/_771/kotlin/Solution.kt

src/_118/kotlin/Solution.kt

@@ -0,0 +1,28 @@
+package _118.kotlin
+
+/**
+ * @author relish
+ * @since 2018/05/03
+ */
+class Solution {
+    fun generate(numRows: Int): List<List<Int>> {
+        val list = ArrayList<ArrayList<Int>>()
+        for (i in 0 until numRows) {
+            val item = ArrayList<Int>()
+            item.add(1)
+            if (i > 1) {
+                for (j in 1 until i) {
+                    val prev = list[i - 1]
+                    item.add(prev[j - 1] + prev[j])
+                }
+            }
+            if (i > 0) item.add(1)
+            list.add(item)
+        }
+        return list
+    }
+}
+
+fun main(args: Array<String>) {
+    println(Solution().generate(7))
+}

tips/118/README.md

@@ -47,6 +47,27 @@ class Solution {
 }
 ```
 
+kotlin(208ms/91.67%):
+```kotlin
+class Solution {
+    fun generate(numRows: Int): List<List<Int>> {
+        val list = ArrayList<ArrayList<Int>>()
+        for (i in 0 until numRows) {
+            val item = ArrayList<Int>()
+            item.add(1)
+            if (i > 1) {
+                for (j in 1 until i) {
+                    val prev = list[i - 1]
+                    item.add(prev[j - 1] + prev[j])
+                }
+            }
+            if (i > 0) item.add(1)
+            list.add(item)
+        }
+        return list
+    }
+}
+```
 
 ## 结语