leetcode

Author: ayoubzulfiqar

MaximumNumberOfCoinsYouCanGet/maximum_number_of_coins_you_can_get.dart

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+/*
+
+-* 1561. Maximum Number of Coins You Can Get *-
+
+
+
+There are 3n piles of coins of varying size, you and your friends will take piles of coins as follows:
+
+In each step, you will choose any 3 piles of coins (not necessarily consecutive).
+Of your choice, Alice will pick the pile with the maximum number of coins.
+You will pick the next pile with the maximum number of coins.
+Your friend Bob will pick the last pile.
+Repeat until there are no more piles of coins.
+Given an array of integers piles where piles[i] is the number of coins in the ith pile.
+
+Return the maximum number of coins that you can have.
+
+ 
+
+Example 1:
+
+Input: piles = [2,4,1,2,7,8]
+Output: 9
+Explanation: Choose the triplet (2, 7, 8), Alice Pick the pile with 8 coins, you the pile with 7 coins and Bob the last one.
+Choose the triplet (1, 2, 4), Alice Pick the pile with 4 coins, you the pile with 2 coins and Bob the last one.
+The maximum number of coins which you can have are: 7 + 2 = 9.
+On the other hand if we choose this arrangement (1, 2, 8), (2, 4, 7) you only get 2 + 4 = 6 coins which is not optimal.
+Example 2:
+
+Input: piles = [2,4,5]
+Output: 4
+Example 3:
+
+Input: piles = [9,8,7,6,5,1,2,3,4]
+Output: 18
+ 
+
+Constraints:
+
+3 <= piles.length <= 105
+piles.length % 3 == 0
+1 <= piles[i] <= 104
+
+
+*/
+
+class Solution {
+  int maxCoins(List<int> piles) {
+    int m = 0;
+  final  int n = piles.length;
+
+    for (int x in piles) {
+      if (x > m) {
+        m = x;
+      }
+    }
+
+  final  List<int> hash = List<int>.filled(m + 1, 0);
+
+    for (int x in piles) {
+      hash[x]++;
+    }
+
+    int bobCoin = n ~/ 3;
+    int startIndex = 1;
+
+    while (bobCoin > 0) {
+      if (hash[startIndex] > 0) {
+        hash[startIndex]--;
+        bobCoin--;
+      } else {
+        startIndex++;
+      }
+    }
+
+    int i = m;
+    int ans = 0;
+    int receive = 0;
+
+    while (i >= startIndex) {
+      if (hash[i] > 0) {
+        ans += receive * i;
+        receive = receive ^ 1;
+        hash[i]--;
+      } else {
+        i--;
+      }
+    }
+
+    return ans;
+  }
+}

MaximumNumberOfCoinsYouCanGet/maximum_number_of_coins_you_can_get.go

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+package main
+
+import "sort"
+
+func maxCoins(piles []int) int {
+	sort.Ints(piles)
+	var n int = len(piles)
+	var kt int = n / 3
+	var i int = n - 2
+	var ans int = 0
+
+	for kt > 0 {
+		kt--
+		ans += piles[i]
+		i = i - 2
+	}
+	return ans
+}