LeetCode_34_FindFirstAndLastPositionofElementinSortedArray
题目分析：
注意，这道题其实是结合上一题，让你明白，我们的写法是只能找最左侧值的。
右侧值可以转换成，大于这个值的最小值，然后下标-1得到。
解法：
public static int[] searchRange(int[] nums, int target) {
int first = findFirst(nums, 0, nums.length - 1, target);
if (-1 != first) {
int last = findLast(nums, 0, nums.length, target);
return new int[]{first, last};
}
return new int[]{-1 ,-1};
}
public static int findFirst(int[] nums, int begin, int end, int target){
while (begin < end){
int mid = begin + (end - begin) / 2;
if(nums[mid] >= target)
end = mid;
else
begin = mid + 1;
}
return nums[begin] == target ? begin : -1;
}
public static int findLast(int[] nums, int begin, int end, int target){
while (begin < end){
int mid = begin + (end - begin) / 2;
if(nums[mid] <= target)
begin = mid + 1;
else
end = mid;
}
return nums[begin - 1] == target ? begin - 1 : -1;
}