标签：ted 存在 pre output log als 而且 tput style
Given the coordinates of four points in 2D space, return whether the four points could construct a square.
The coordinate (x,y) of a point is represented by an integer array with two integers.
Example:
Input: p1 = [0,0], p2 = [1,1], p3 = [1,0], p4 = [0,1]
Output: True
Note:
All the input integers are in the range [-10000, 10000].
A valid square has four equal sides with positive length and four equal angles (90-degree angles).
Input points have no order.
思路：
4个点，求出任意两点之间的距离，总共6条线段，存在其中4条相等，而且另外两条也相等就是正方形。
double length(vector<int>& p1, vector<int>& p2) { int x = abs(p1[0] - p2[0]); int y = abs(p1[1] - p2[1]); return x*x + y*y; } bool validSquare(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4) { map<double,int>table; table[length(p1,p2)]++; table[length(p1,p3)]++; table[length(p1,p4)]++; table[length(p2,p3)]++; table[length(p2,p4)]++; table[length(p3,p4)]++; if(table.size()!=2) return false; map<double ,int>::iterator it = table.begin(); map<double ,int>::iterator temp = it; temp++; if((it->second ==4 && temp->second ==2 ) ||(it->second ==2 && temp->second ==4) )return true; return false; }
参考：
http://blog.csdn.net/yuer158462008/article/details/47374545
标签：ted 存在 pre output log als 而且 tput style
原文地址：http://www.cnblogs.com/hellowooorld/p/6884360.html
