problem1 link 暴力即可.因为即便所有数字的和是50,50所有的不同的划分数只有204226中.所以最长的循环也就这么大. problem2 link 令$f[i][j]$表示有$i$个红色和$j$个黑色时最大的期望,那么: (1)当$j=0$时,$f[i][0]=f[i-1][0]+1$; (2)当$j>0$但是$i=0$时,$f[i][j]=0$; (3)当$j>0$且$i>0$时,$f[i][j]=max(0,(f[i-1][j]+1)*\frac{i}{i+j}+(f…
problem1 link 倒着想.每次添加一个右括号再添加一个左括号,直到还原.那么每次的右括号的选择范围为当前左括号后面的右括号减去后面已经使用的右括号. problem2 link 令$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…
