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isaiahliu · Nov 28, 2024 · f50d07a · f50d07a
1 parent f7cfce2
commit f50d07a
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Showing 2 changed files with 45 additions and 6 deletions.
diff --git a/src/main/kotlin/p32xx/Problem3250.kt b/src/main/kotlin/p32xx/Problem3250.kt
@@ -5,23 +5,29 @@ import util.expect
 fun main() {
     class Solution {
         fun countOfPairs(nums: IntArray): Int {
-            val m = 1000000007L
+            val m = 1000000007
 
-            var dp = LongArray(nums[0] + 1) { 1 }
+            var dp = IntArray(nums[0] + 1) { it + 1 }
 
             for (index in 1 until nums.size) {
-                dp = LongArray(nums[index] + 1) { cur ->
-                    (0..cur).filter { nums[index - 1] - it >= nums[index] - cur }.sumOf { dp.getOrElse(it) { 0L } } % m
+                var sum = 0
+                dp = IntArray(nums[index] + 1) { cur ->
+                    dp.getOrNull(minOf(nums[index - 1] - nums[index], 0) + cur)?.also {
+                        sum += it
+                        sum %= m
+                    }
+
+                    sum
                 }
             }
 
-            return (dp.sum() % m).toInt()
+            return dp.last()
         }
     }
 
     expect {
         Solution().countOfPairs(
-            intArrayOf()
+            intArrayOf(2, 3, 2)
         )
     }
 }
diff --git a/src/main/kotlin/p32xx/Problem3251.kt b/src/main/kotlin/p32xx/Problem3251.kt
@@ -0,0 +1,33 @@
+package p32xx
+
+import util.expect
+
+fun main() {
+    class Solution {
+        fun countOfPairs(nums: IntArray): Int {
+            val m = 1000000007
+
+            var dp = IntArray(nums[0] + 1) { it + 1 }
+
+            for (index in 1 until nums.size) {
+                var sum = 0
+                dp = IntArray(nums[index] + 1) { cur ->
+                    dp.getOrNull(minOf(nums[index - 1] - nums[index], 0) + cur)?.also {
+                        sum += it
+                        sum %= m
+                    }
+
+                    sum
+                }
+            }
+
+            return dp.last()
+        }
+    }
+
+    expect {
+        Solution().countOfPairs(
+            intArrayOf()
+        )
+    }
+}