Create 0646-maximum-length-of-pair-chain.kt

Author: a93a

kotlin/0646-maximum-length-of-pair-chain.kt

@@ -0,0 +1,36 @@
+//greedy algorithm O(nlogn)
+class Solution {
+    fun findLongestChain(_pairs: Array<IntArray>): Int {
+        val pairs = _pairs.sortedWith(compareBy({ it[1] }, { it[0] }))
+
+        var res = 1
+        var time = pairs[0][1]
+        for (i in 1 until pairs.size) {
+            if(pairs[i][0] > time) {
+                res++
+                time = pairs[i][1]
+            }
+        }
+
+        return res
+    }
+}
+
+//dp O(n^2)
+class Solution {
+    fun findLongestChain(_pairs: Array<IntArray>): Int {
+        val pairs = _pairs.sortedWith(compareBy({ it[0] }, { it[1] }))
+        val n = pairs.size
+        val dp = IntArray(n) { 1 }
+
+        for (i in 0 until n) {
+            for (j in 0 until n) {
+                if (pairs[i][0] > pairs[j][1]) {
+                    dp[i] = maxOf(dp[i], dp[j] + 1)
+                }
+            }
+        }
+
+        return dp[n - 1]
+    }
+}