problem1 link $N+1$到$M$ 之间的数字要包含所有1到$N$之间出现的质因子的最高幂即可. problem2 link 从第一个节点到第$N$个节点依次考虑.对于第$i$个节点来说,其颜色为$j$时,可以选择与前面的连边或者不连边,方案数为$1+(i-1)+g(i-1,j)$.其中$g(x,y)$ 表示前$x$个节点中,颜色为$y$ 的节点的个数 所以节点$i$的方案数为$f(i)=\sum_{j=1}^{K}(1+i-1-g(i-1,j))=K*i-\sum_{j=1}^{K…
problem1 link 倒着想.每次添加一个右括号再添加一个左括号,直到还原.那么每次的右括号的选择范围为当前左括号后面的右括号减去后面已经使用的右括号. problem2 link 令$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…
