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FirstAndLastPosition.java
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FirstAndLastPosition.java
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public class FirstAndLastPosition {
public static void main(String[] args) {
}
public static int[] searchRange(int[] nums, int target) {
int[] ans = {-1, -1};
// check for first occurence if target first
int start = search(nums,target, true);
int end = search(nums,target, false);
ans[0] = start;
ans[1] = end;
return ans;
}
// this function just returns the index value of target
static int search(int[] nums, int target, boolean findStartIndex){
int ans = -1;
int start=0;
int end=nums.length-1;
while(start<=end){
// find the middle element
// int mid = (start +end)/2; // might be possible that (start+end) exceeds the range of int in java
int mid = start + (end-start)/2;
if (target<nums[mid]){
end=mid-1;
} else if (target>nums[mid]) {
start=mid+1;
}
else{
// potential ans is found
ans = mid;
if (findStartIndex){
end= mid-1;
}else {
start = mid+1;
}
}
}
return ans;
}
}