zll00561的专栏

A small frog wants to get to the other side of a river. The frog is currently located at position 0, and wants to get to position X. Leaves fall from a tree onto the surface of the river. You are give

You are given N counters, initially set to 0, and you have two possible operations on them: increase(X) − counter X is increased by 1, max counter − all counters are set to the maximum value of any c

A non-empty zero-indexed array A consisting of N integers is given. A permutation is a sequence containing each element from 1 to N once, and only once. For example, array A such that: A[0] = 4

A non-empty zero-indexed array A consisting of N integers is given. The consecutive elements of array A represent consecutive cars on a road. Array A contains only 0s and/or 1s: 0 represents a car tr

给定一个数组N个正整数，给每个数一个符号，正或者负使得所有数的的和的绝对值尽可能大。也就是使得这个 val(A, S) = |sum{ A[i]*S[i] for i = 0..N−1 }尽可能大s[i] = +1或者-1。 通过分析可以发现元素的正负不影响结果，问题转化为将数分成两堆，两堆只差最小。首先将元素全部转成正数顺便做了个count sort. 发现这个问题转化为多重背包问题。 DP