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class Solution {
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  public int romanToInt(String s) {
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    int res = 0;
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    // Let s = "IV" after traversing string res will be 6
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    // Let s= "IX" after traversing string res will be 11
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    for (int i = 0; i < s.length(); i++) {
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      switch (s.charAt(i)) {
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        case 'I':
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          res = res + 1;
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          break;
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        case 'V':
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          res = res + 5;
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          break;
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        case 'X':
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          res += 10;
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          break;
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        case 'L':
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          res += 50;
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          break;
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        case 'C':
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          res += 100;
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          break;
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        case 'D':
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          res += 500;
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          break;
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        case 'M':
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          res += 1000;
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          break;
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      }
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    }
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    // Since s= "IV" it satisfies first condition and 2 is subtracted from res. res=4
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    // Since s= "IX" it satisfies first condition and 2 is subtracted from res. res=9
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    if (s.contains("IV") || s.contains("IX")) res = res - 2;
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    if (s.contains("XL") || s.contains("XC")) res = res - 20;
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    if (s.contains("CD") || s.contains("CM")) res = res - 200;
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    return res;
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  }
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}