zoj 3647 Gao the Grid

【zoj 3647 Gao the Grid】的更多相关文章

ZOJ 3647 Gao the Grid dp,思路,格中取同一行的三点,经典难度:3

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=4837 三角形的总数=格子中任取3个点的组合数-同一横行任取3个点数目-同一纵行任取3个点数目-同一斜直线上任取3个点数目同一横行和同一纵行都好求同一斜行的距离最远的点必然是一个矩形的两个端点,设矩形的长宽为l,w,中间可以取的点数则是(gcd(l,w)-1),左上角或左下角的起点反而不重要. 能够取到该矩形的可能是 (n-l+1)*(m-w+1),因为左上角作为起点或左下…

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=4837 先求出从所有点随机找出三个点的组合数,然后去掉共线的,平行好去掉,斜线就需要枚举矩形,也就是枚举两个端点形成向量. #include <cstdio> #include <cstring> #include <algorithm> #define maxn 1000 #define ll long long using namespace st…

ZOJ 3780 Paint the Grid Again（隐式图拓扑排序）

Paint the Grid Again Time Limit: 2 Seconds Memory Limit: 65536 KB Leo has a grid with N × N cells. He wants to paint each cell with a specific color (either black or white). Leo has a magical brush which can paint any row with black color, or an…

ZOJ 3781 Paint the Grid Reloaded（BFS+缩点思想）

Paint the Grid Reloaded Time Limit: 2 Seconds Memory Limit: 65536 KB Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are called connected if they share an edge and they are…

ZOJ 3781 Paint the Grid Reloaded（BFS）

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3781 Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are called connected if they share an edge and they are in…

zoj 3672 Gao The Sequence

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=4915题意:a[k]-一个任意的数,这个数要等于a[1]~a[k]每个数减去任意一个数,经过多次这样的变换到达目标b序列,能到达就yes不能到达距no思路:既然a[k]前面数相减等于这个数,则所有减去的数之和sum一定数偶数.其中最大的减数的2倍一定要小于这个sum,如果不满足就不可能从a序列到b序列.Gao The Sequence Time Limit: 2 Seconds…

zoj 3647 智商题

此题就是求格点中三角形的个数. 就是找出三点不共线的个数. n*m的矩形中有(n+1)*(m+1)个格点. 选出三个点的总个数为:C((n+1)*(m+1),3). 减掉共线的情况就是答案了. 首先是水平和垂直共线的情况:C(n+1,3)*(m+1)+C(m+1,3)*(n+1); 然后斜的共线的情况就是枚举矩形. 斜着共线的三点用枚举法n*m的矩形,对角两个点中间共有gcd(m,n)-1个点,两条对角线,所以数量*2,大矩形里共有(N-n+1)*(M-m+1)个的矩形,一并去除 #includ…