LeetCode 836. Rectangle Overlap

题目

An axis-aligned rectangle is represented as a list [x1, y1, x2, y2], where (x1, y1) is the coordinate of its bottom-left corner, and (x2, y2) is the coordinate of its top-right corner. Its top and bottom edges are parallel to the X-axis, and its left and right edges are parallel to the Y-axis.

Two rectangles overlap if the area of their intersection is positive. To be clear, two rectangles that only touch at the corner or edges do not overlap.

Given two axis-aligned rectangles rec1 and rec2, return true if they overlap, otherwise return false.

思路

如果两个长方形不overlap，rec1在rec2的左边/右边/上边/下边。如果两个长方形overlap是反过来的。

答案

public boolean isPowerOfThree(int n) {
        while(n>=3){
            if(n%3!=0) return false;
            n/=3;
        }
        return n==1;
    }
}