Improved task 274.

Author: javadev

README.md

@@ -3509,7 +3509,7 @@ implementation 'com.github.javadev:leetcode-in-java:1.15'
 | 0279 |[Perfect Squares](src.save/main/java/g0201_0300/s0279_perfect_squares/Solution.java)| Medium | Top_Interview_Questions, Dynamic_Programming, Math, Breadth_First_Search, Dynamic_Programming_I_Day_21 | 1 | 100.00
 | 0278 |[First Bad Version](src.save/main/java/g0201_0300/s0278_first_bad_version/Solution.java)| Easy | Binary_Search, Interactive, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_5, Level_1_Day_7_Binary_Search | 15 | 87.89
 | 0275 |[H-Index II](src.save/main/java/g0201_0300/s0275_h_index_ii/Solution.java)| Medium | Array, Binary_Search, Binary_Search_II_Day_8 | 0 | 100.00
-| 0274 |[H-Index](src.save/main/java/g0201_0300/s0274_h_index/Solution.java)| Medium | Array, Sorting, Counting_Sort | 3 | 45.78
+| 0274 |[H-Index](src.save/main/java/g0201_0300/s0274_h_index/Solution.java)| Medium | Array, Sorting, Counting_Sort | 0 | 100.00
 | 0273 |[Integer to English Words](src.save/main/java/g0201_0300/s0273_integer_to_english_words/Solution.java)| Hard | String, Math, Recursion, Udemy_Strings | 3 | 95.67
 | 0268 |[Missing Number](src.save/main/java/g0201_0300/s0268_missing_number/Solution.java)| Easy | Top_Interview_Questions, Array, Hash_Table, Math, Sorting, Binary_Search, Bit_Manipulation | 1 | 72.07
 | 0264 |[Ugly Number II](src.save/main/java/g0201_0300/s0264_ugly_number_ii/Solution.java)| Medium | Hash_Table, Dynamic_Programming, Math, Heap_Priority_Queue, Dynamic_Programming_I_Day_11 | 2 | 99.91

src.save/main/java/g0201_0300/s0274_h_index/Solution.java

@@ -1,36 +1,21 @@
 package g0201_0300.s0274_h_index;
 
-// #Medium #Array #Sorting #Counting_Sort #2022_07_06_Time_3_ms_(45.78%)_Space_41.7_MB_(75.73%)
-
-import java.util.Arrays;
+// #Medium #Array #Sorting #Counting_Sort #2022_11_05_Time_0_ms_(100.00%)_Space_40.3_MB_(86.98%)
 
 public class Solution {
     public int hIndex(int[] citations) {
-        // Sort array then traverse from end keep track of counter denoting total elements seen so
-        // far
-        Arrays.sort(citations);
-        int count = 0;
-        int hIndex = 0;
-        for (int i = citations.length - 1; i >= 0; i--) {
-            if (i == citations.length - 1 && count == citations[i]) {
-                hIndex = citations[i];
-                return hIndex;
-                //  Ex:- 7 10--> counter =8
-            } else if (citations[i] <= count && count < citations[i + 1]) {
-                hIndex = count;
-                return hIndex;
-                // Ex:- 7 9 --> counter 6 (incuding 7 there willbe 7 elements)
-            } else if (citations[i] == count + 1) {
-                hIndex = count + 1;
-                return hIndex;
-            } else {
-                count++;
-            }
+        int len = citations.length;
+        int[] freqArray = new int[len + 1];
+        for (int citation : citations) {
+            freqArray[Math.min(citation, len)]++;
         }
-        // case when no element is hindex so far
-        if (count < citations[0]) {
-            hIndex = count;
+        int total_so_far = 0;
+        for (int k = len; k >= 0; k--) {
+            total_so_far += freqArray[k];
+            if (total_so_far >= k) {
+                return k;
+            }
         }
-        return hIndex;
+        return -1;
     }
 }