Create 0494-target-sum.kt

Arrrsh · May 4, 2023 · d4d8e65 · d4d8e65
1 parent c385d4d
commit d4d8e65
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/kotlin/0494-target-sum.kt b/kotlin/0494-target-sum.kt
@@ -0,0 +1,18 @@
+class Solution {
+ fun findTargetSumWays(nums: IntArray, target: Int): Int {
+ val memo = HashMap<String, Int>()
+
+ fun dfs(i: Int, sum: Int): Int {
+ if (i == nums.size)
+ return if (sum == target) 1 else 0
+ val key = "$i:$sum"
+ if (key in memo)
+ return memo[key]!!
+ memo[key] = dfs(i + 1, sum + nums[i]) + 
+ dfs(i + 1, sum - nums[i])
+ return memo[key]!!
+ }
+
+ return dfs(0, 0)
+ }
+}