update

Author: OneCodeMonkey

codeForces/Codeforces_1300B_Assigning_to_Classes.java

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+// AC: 702 ms  
+// Memory: 1400 KB
+// sort & greedy.
+// T:O(sum(ni)), S:O(max(ni))
+// 
+import java.util.Arrays;
+import java.util.Scanner;
+
+public class Codeforces_1300B_Assigning_to_Classes {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int t = sc.nextInt();
+        for (int i = 0; i < t; i++) {
+            int n = sc.nextInt(), ret = 0;
+            int[] arr = new int[2 * n];
+            for (int j = 0; j < 2 * n; j++) {
+                int a = sc.nextInt();
+                arr[j] = a;
+            }
+            Arrays.sort(arr);
+
+            System.out.println(arr[n] - arr[n - 1]);
+        }
+    }
+}

codeForces/Codeforces_2062A_String.java

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+// Time: 374 ms 
+// Memory: 500 KB
+// .
+// T:O(n), S:O(1)
+// 
+import java.util.Scanner;
+
+public class Codeforces_2062A_String {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int t = sc.nextInt();
+        for (int i = 0; i < t; i++) {
+            String s = sc.next();
+            int ret = 0;
+            for (char c : s.toCharArray()) {
+                if (c == '1') {
+                    ret++;
+                }
+            }
+
+            System.out.println(ret);
+        }
+    }
+}

leetcode_solved/leetcode_3507_Minimum_Pair_Removal_to_Sort_Array_I.java

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+// Runtime 3 ms Beats 62.16%
+// Memory 42.87 MB Beats 64.36%
+// brute-force.
+// T:O(n^2), S:O(n)
+//
+class Solution {
+    public int minimumPairRemoval(int[] nums) {
+        ArrayList<Integer> a = new ArrayList<>();
+        for (int i : nums) a.add(i);
+        int ans = 0;
+        while (a.size() >= 2 && !f(a)) {
+            ans++;
+            int l1 = -1;
+            int l2 = -1;
+            int max = Integer.MAX_VALUE;
+            for (int i = 1; i < a.size(); i++) {
+                int s = a.get(i) + a.get(i - 1);
+                if (s < max) {
+                    l1 = i;
+                    l2 = i - 1;
+                    max = s;
+                }
+
+            }
+
+            a.remove(l1);
+            a.add(l1, max);
+            a.remove(l2);
+        }
+        return ans;
+    }
+
+    public boolean f(ArrayList<Integer> a) {
+        for (int i = 1; i < a.size(); i++) {
+            if (a.get(i) < a.get(i - 1)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}