Roman to Integer Leetcode

Given a Roman numeral, convert it to an integer.

Input is guaranteed to being within the range from 1 to 3999.

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Ⅰ (1) Ⅴ (5) Ⅹ (Ten) L (+) C (+) D (+) M (1000)

Rule: At the back of a large number as a addend, in the front of the large number as a meiosis

such as: ⅲ=3,ⅳ=4,ⅵ=6,ⅹⅸ=19,ⅹⅹ=20,ⅹlⅴ=45,mcmⅹⅹc=1980

Starting from the lowest bit, if the previous number is larger than it, let the previous value precede it, and if it is smaller, let the current value minus the previous value

intRomantoint (strings) {if(s.length () = =0)return 0; intLen =s.length (); Unordered_map<Char,int>map; Map.insert (Make_pair ('I',1)); Map.insert (Make_pair ('V',5)); Map.insert (Make_pair ('X',Ten)); Map.insert (Make_pair ('L', -)); Map.insert (Make_pair ('C', -)); Map.insert (Make_pair ('D', -)); Map.insert (Make_pair ('M', +)); intresult = map.at (s.at (Len-1)); intPivot =result;  for(inti = len-2; I >=0; i--) {        intCurr =map.at (s.at (i)); if(Curr >=pivot) {Result+=Curr; }        Else{result-=Curr; } Pivot=Curr; }    returnresult;}

Roman to Integer Leetcode