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Merge pull request #559 from Aryan-Srivastava/majority-element
majority element in an array
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Program's_Contributed_By_Contributors/Java_Programs/Misc/majority_Element.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,71 @@ | ||
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| // import java.util.Arrays; | ||
| import java.util.HashMap; | ||
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| public class majority_Element { | ||
| public static void main(String[] args) { | ||
| int[] nums = { 2, 2, 1, 1, 1, 2, 2 }; | ||
| int answer = optimal(nums); | ||
| System.out.println(answer); | ||
| } | ||
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| // private static int brute(int[] nums) { | ||
| // int n = nums.length; | ||
| // for (int i = 0; i < n; i++) { | ||
| // int count = 0; | ||
| // int element = nums[i]; | ||
| // for (int j = 0; j < n; j++) { | ||
| // if (i != j) { | ||
| // if (nums[j] == element) { | ||
| // count++; | ||
| // } | ||
| // } | ||
| // if (count > n / 2) { | ||
| // return element; | ||
| // } | ||
| // } | ||
| // } | ||
| // return -1; | ||
| // } | ||
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| // private static int better1(int[] nums) { | ||
| // Arrays.sort(nums); | ||
| // if (nums.length <= 1) | ||
| // return nums[0]; | ||
| // Arrays.sort(nums); | ||
| // int count = 1; | ||
| // for (int i = 0; i < nums.length - 1; i++) { | ||
| // if (nums[i] == nums[i + 1]) { | ||
| // count++; | ||
| // } else { | ||
| // count = 1; | ||
| // } | ||
| // if (count > nums.length / 2) | ||
| // return nums[i]; | ||
| // } | ||
| // return -1; | ||
| // } | ||
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| // private static int better2(int[] nums) { | ||
| // Arrays.sort(nums); | ||
| // return nums[nums.length / 2]; | ||
| // } | ||
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| private static int optimal(int[] nums) { | ||
| if (nums.length <= 1) | ||
| return nums[0]; | ||
| HashMap<Integer, Integer> map = new HashMap<Integer, Integer>(); | ||
| for (int i = 0; i < nums.length; i++) { | ||
| if (map.containsKey(nums[i])) { | ||
| int count = map.get(nums[i]) + 1; | ||
| if (count > nums.length / 2) | ||
| return nums[i]; | ||
| else | ||
| map.put(nums[i], count); | ||
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| } else | ||
| map.put(nums[i], 1); | ||
| } | ||
| return -1; | ||
| } | ||
| } |