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LeetCode OJ: 34. Search for a Range

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題目連結，解法為從陣列左右兩邊各用Binary Search找一次。

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public class Solution {
    public int[] searchRange(int[] nums, int target) {
        int n = nums.length;
        int left = 0, right = n - 1;
        int[] result = new int[] { -1, -1 };
    
        // The left boundary
        while (left < right)
        {
            int mid = (left + right) /2;
            if (nums[mid] < target) left = mid + 1;
            else right = mid;
        }
        if (nums[left] != target) return result;
        else result[0] = left;
    
        // The right boundary
        right = n-1;
        while (left < right)
        {
            int mid = (left + right) / 2 + 1;
            if (nums[mid] > target) right = mid - 1;  
            else left = mid;
        }
        
        result[1] = right;
        return result;
    }
}

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