摘要：
Given a square array of integers A, we want the minimum sum of a falling path through A. A falling path starts at any element in the first row, and ch 阅读全文
摘要：
In an array A of 0s and 1s, how many non-empty subarrays have sum S? Example 1: Note: 通用解法就是求连续数组的和有多少个，这种题代码都不会变的 把和存起来，给后面的数字-S看有没有这个和，有的话加起来，然后a[an 阅读全文
摘要：
Every email consists of a local name and a domain name, separated by the @ sign. For example, in alice@leetcode.com, alice is the local name, and leet 阅读全文