Search for a Range

標籤：

public class Solution {    public int[] searchRange(int[] A, int target) {        int[] res = {-1, -1};        if(A==null || A.length<1) return res;        int ll = 0, lr = A.length-1, rl=0,rr = A.length-1;        while(ll<=lr){            int m = (ll+lr)/2;            if(A[m]<target){                ll=m+1;            }else                  lr= m-1;        }        while(rl<=rr){            int m = (rl+rr)/2;            if(A[m]<=target){// 如果是< 就錯了，因為rr的位置和ll一樣，必然不可以是等於的情況                rl=m+1;            }else                  rr= m-1;        }        if(ll<=rr){            res[0] = ll;            res[1] = rr;        }        return res;    }}

二分法和夾逼法

ref

http://blog.csdn.net/linhuanmars/article/details/20593391

Search for a Range