problem1 link $f[u][0],f[u][1]$表示$u$节点表示的子树去掉和不去掉节点$u$的最大权值. problem2 link 首先预处理计算任意三个蓝点组成的三角形中的蓝点个数以及是否包含红点.凸包可以分割成三角形.首先初始化凸包的三个顶点为$x,y,z$(假设$x,y,z$是逆时针),然后每次增加一个新的点进来,设最后加入凸包的两个点为$p_{1},p_{2}$,新加入的点为$q$,那么$q$需要满足的条件为: (1)三角形$x,p_{2},q$中没有红点: (2)$q…
problem1 link 倒着想.每次添加一个右括号再添加一个左括号,直到还原.那么每次的右括号的选择范围为当前左括号后面的右括号减去后面已经使用的右括号. problem2 link 令$h(x)=\sum_{i=1}^{x}g(i)$,那么答案为$h(R)-h(L-1)$.对于$h(x)$: (1)如果$x\leq K$,那么$h(x)=0$ (2)否则对于$[K+1,x]$之间的所有偶数来说,对答案的贡献为$even+h(\frac{x}{2})-h(\frac{K}{2})$,其中$e…
Problem Statement You are given the ints perimeter and area. Your task is to find a triangle with the following properties: The coordinates of each vertex are integers between 0 and 3000, inclusive. The perimeter of the triangle must be exactly…
Problem Statement The Happy Letter game is played as follows: At the beginning, several players enter the field. Each player has a lowercase English letter on their back. The game is played in turns. In each turn, you select two players with dif…
