package javaLeetCode.primary;

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Stack;

public class RomanToInteger_13 {
    public static void main(String[] args) {
        System.out.println("Please input a roman numeral:");
        @SuppressWarnings("resource")
        Scanner input = new Scanner(System.in);
        String s = input.next();
        System.out.println(romanToInt_3(s));
    }// end main()

    /**
     * Conventional thinking.
     * Scan from head to tail and use Map or Array.
     */
    /*
     * Test Data:
     * III--3
     * IV--4
     * IX--9
     * LVIII--58
     * MCMXCIV--1994
     * MCCCXIV--1314
     * MMMIX--3009
     * MMMCCXLIX--3249
     */
    public static int romanToInt_1(String s) {
        char[] str = s.toCharArray();
        Map<Character, Integer> map = new HashMap<Character, Integer>();
        map.put('I', 1);
        map.put('V', 5);
        map.put('X', 10);
        map.put('L', 50);
        map.put('C', 100);
        map.put('D', 500);
        map.put('M', 1000);

        int num = 0;
        for (int i = 0; i < s.length() - 1; i++) {
            if (map.get(str[i]) >= map.get(str[i + 1])) {
                num += map.get(str[i]);
            } else {
                num -= map.get(str[i]);
            } // end if
        } // end for
        num += map.get(str[str.length - 1]);
        return num;
    }// end romanToInt()

    /**
     * Conventional thinking.
     * Scan from head to tail and use Stack to reserve the total.
     */
    public static int romanToInt_2(String s) {
        char[] str = s.toCharArray();
        Stack <Integer>romanStack = new Stack<Integer>();
        Map<Character, Integer> map = new HashMap<Character, Integer>();
        map.put('I', 1);
        map.put('V', 5);
        map.put('X', 10);
        map.put('L', 50);
        map.put('C', 100);
        map.put('D', 500);
        map.put('M', 1000);

        int num = 0;
        romanStack.push(map.get(str[0]));
        for (int i = 1; i < s.length() ; i++) {
            if (map.get(str[i]) <= map.get(str[i - 1])) {
                romanStack.push(map.get(str[i]));
            } else {
                romanStack.push(map.get(str[i])-romanStack.pop());
            } // end if
        } // end for

        //Don't write "for(int I =0;I < romanStack. The size ();I++) ",
        //because the stack size is fetched every time the loop occurs
        int length = romanStack.size();
        for(int i=0;i<length;i++) {
            num += romanStack.pop();
        }//end for
        return num;
    }// end romanToInt()

    public static int romanToInt_3(String s) {
        int num = 0;
        for(int i=0;i<s.length();i++) {
            char c = s.charAt(i);
            if(c=='I') {num += 1;}
            if(c=='V') {num += 5;}
            if(c=='X') {num += 10;}
            if(c=='L') {num += 50;}
            if(c=='C') {num += 100;}
            if(c=='D') {num += 500;}
            if(c=='M') {num += 1000;}

        }//end for

        if(s.contains("IV")) {num -= 2;}
        if(s.contains("IX")) {num -= 2;}
        if(s.contains("XL")) {num -= 20;}
        if(s.contains("XC")) {num -= 20;}
        if(s.contains("CD")) {num -= 200;}
        if(s.contains("CM")) {num -= 200;}

        return num;
    }// end romanToInt()
}// end RomanToInteger_13