34. Search for a Range

 

<p style="margin-top: 0px; margin-bottom: 10px; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; line-height: 30px;">Given a sorted array of integers, find the starting and ending position of a given target value.</p><p style="margin-top: 0px; margin-bottom: 10px; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; line-height: 30px;">Your algorithm's runtime complexity must be in the order of <span style="box-sizing: border-box;">O</span>(log <span style="box-sizing: border-box;">n</span>).</p><p style="margin-top: 0px; margin-bottom: 10px; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; line-height: 30px;">If the target is not found in the array, return <code style="box-sizing: border-box; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 12.6px; padding: 2px 4px; color: rgb(199, 37, 78); border-radius: 4px; background-color: rgb(249, 242, 244);">[-1, -1]</code>.</p><p style="margin-top: 0px; margin-bottom: 10px; box-sizing: border-box; color: rgb(51, 51, 51); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; line-height: 30px;">For example,<br style="box-sizing: border-box;" />Given <code style="box-sizing: border-box; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 12.6px; padding: 2px 4px; color: rgb(199, 37, 78); border-radius: 4px; background-color: rgb(249, 242, 244);">[5, 7, 7, 8, 8, 10]</code> and target value 8,<br style="box-sizing: border-box;" />return <code style="box-sizing: border-box; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 12.6px; padding: 2px 4px; color: rgb(199, 37, 78); border-radius: 4px; background-color: rgb(249, 242, 244);">[3, 4]</code>.</p>

<p>
</p><p>public class Solution {</p>    public int[] searchRange(int[] A, int target) {
int start = Solution.firstsearch(A, target);
if (start == A.length || A[start] != target) {
return new int[]{-1, -1};
}
return new int[]{start, Solution.firstsearch(A, target + 1) - 1};
}
public static int firstsearch(int []s,int target){
int low=0;
int high=s.length-1;
while(low<=high){
int mid=(low+high)/2;
if(s[mid]<target){
low=mid+1;
}
else{
high=mid;
}
}
return low;   目标值的最小序数是low
}
}

public class Solution {
public int[] searchRange(int[] nums, int target) {
int[] ret= {-1, -1};
int i=0; int j=nums.length-1;
int m;

while (i<j) {
m=i+((j-i-1)>>1);
if(nums[m] < target) {
i=m+1;
} else {
j=m; //j是找到的目标值的最前的位置
}
}
if(nums[j]==target) {
ret[0] = j; //如果有j==target 那就是目标值的第一个 如果不是那就没有目标值

i=j; j=nums.length-1;
while (i<j) {
m=i+((j-i+1)>>1);
if(nums[m] > target) {
j=m-1;
} else {
i=m;
}
}
ret[1] = i;
}

return ret;
}
}

没写完。。