code第一部分:数组 第十四题 雨水问题 Given n non-negative integers representing an elevation map where the width of each bar is 1, computehow much water it is able to trap after raining.For example, Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6. 分析: 解决方案1 对于每个柱子,找到其左右两