42. Trapping Rain Water leetcode Python 2016 new season
Given n non-negativeintegersrepresentinganelevationmapwherethewidthofeachbaris1,computehowmuchwateritisabletotrapafterraining.Forexample, Given [0,1,0,2,1,0,1,3,2,1,2,1],return 6.Theaboveelevationmapi