题解 | #二分查找#

import java.util.*;
public class BinarySearch {
    public int getPos(int[] A, int n, int val) {
        // write code here
        int left = 0, right = n - 1;
        boolean exist = false;
        while(left <= right){
            int mid = (left + right) / 2;
            if(A[mid] == val) exist = true;
            if(A[mid] >= val){
                right = mid - 1;
            }else{
                left = mid + 1;
            }
        }
        if(exist == false) return -1;
        else return right + 1;
    }
}