package leetcode;

public class ValidRoman {

boolean validroman(String s){

char[] romans = {'M','D','C','L','X','V','I'};

int[] values = {1000,500,100,50,10,5,1};

int l = s.length();

if(l== 0)

return false;

int count = 1;

boolean can_reverse = true; // next char index can be smaller than current char index;

for(int i=0;i<l-1;i++){

int current = findindex(romans,s.charAt(i));

int next = findindex(romans,s.charAt(i+1));

if(current == -1 || next == -1)

return false;

if(current == next){

count++;

if(count == 4)

return false;

if(current %2 == 0)

continue;

}

else{

count = 1;

if(current < next)

continue;

else if(current - next == 2){

if(i == 0)

continue;

if(i>0){

int prev = findindex(romans, s.charAt(i-1));

if(prev < next)

continue;

}

}

}

return false;

}

return true;

}

int findindex(char[] romans,char c){

for(int i=0;i<romans.length;i++){

if(romans[i] == c)

return i;

}

return -1;

}

public static void main(String[] args) {

ValidRoman vr = new ValidRoman();

System.out.println(vr.validroman("VX") == false);

System.out.println(vr.validroman("VV") == false);

System.out.println(vr.validroman("II") == true);

System.out.println(vr.validroman("IIX") == false);

System.out.println(vr.validroman("IX") == true);

System.out.println(vr.validroman("IM") == false);

System.out.println(vr.validroman("XM") == false);

System.out.println(vr.validroman("CM") == true);

System.out.println(vr.validroman("MMMDCCCC") == false);

}

}

// VX false

// VV false

// II true

// IIX false

// IX true

// IM false

// XM false

// CM true