[LeetCode] Search in Rotated Sorted Array

标签：leetcode

    public int search(int[] A, int target) {
        return bsearch(A, target, 0, A.length - 1);
    }

    /**
     * 二分搜索，无重复元素，判断是否为rotated
     * @param A
     * @param target
     * @param l
     * @param r
     * @return
     */
    public int bsearch(int[] A, int target, int l, int r) {
        if(l <= r){
            int mid = r + (l - r) / 2;
            if(A[l] > A[r]){//无序的情况
                if(target >  A[l]){
                    if(A[l] > A[mid]) return bsearch(A, target, l + 1, mid);
                    else {
                        if(target >= A[mid])return bsearch(A, target, mid, r);
                        else return bsearch(A, target, l + 1, mid -1 );
                    }
                }else if(target == A[l])  return l;
                else {
                    if(A[l] > A[mid]){
                        if(target > A[mid]) return bsearch(A, target, mid + 1, r);
                        else return bsearch(A, target, l + 1, mid);
                    }else {
                        return bsearch(A, target, mid + 1, r);
                    }
                }
            }else {//有序的情况
                if(target == A[mid]) return mid;
                if(target > A[mid]) return bsearch(A, target, mid+1, r);
                else return bsearch(A, target, l, mid - 1);
            }

        }else return -1;
    }

[LeetCode] Search in Rotated Sorted Array

标签：leetcode

原文地址：http://blog.csdn.net/youmengjiuzhuiba/article/details/45110467