[LeetCode]Roman to Integer

var romanToInt = function(s) {
    var array=[];
        for(var i=0;i<s.length;i++){
            var word=s.substring(i,i+1);
            switch (word){
                case "I":
                    array[i]=1;
                    break;
                case "V":
                    array[i]=5;
                    break;
                case "X":
                    array[i]=10;
                    break;
                case "L":
                    array[i]=50;
                    break;
                case "C":
                    array[i]=100;
                    break;
                case "D":
                    array[i]=500;
                    break;
                case "M":
                    array[i]=1000;
                    break;
            }
                
        }
        var result=array[0];
        for(var j=0;j<(array.length-1);j++){
            if(array[j+1]>array[j]){
                result+=(array[j+1]-array[j]*2)
            }else{
                result+=array[j+1];
            }
        }
        return result;
    
};