string O(n) O(1)

Author: lukeist

leetcode-13-RomanToInteger.js

@@ -1,14 +1,3 @@
-/**
- * @param {string} s
- * @return {number}
- */
-
-// p: string;
-// r: int;
-
-//      i
-// MCMXCIVX
-//      j
 const regular = {
   I: 1,
   V: 5,
@@ -19,35 +8,84 @@ const regular = {
   M: 1000,
 };
 
-const special = {
-  IV: 4,
-  IX: 9,
-  XL: 40,
-  XC: 90,
-  CD: 400,
-  CM: 900,
-};
-
 var romanToInt = function (s) {
-  let i = 0,
-    j = 1;
-  let count = 0;
-  while (i < s.length) {
-    if (s[i] + s[j] in special) {
-      console.log(s[i] + s[j]);
-      count += special[s[i] + s[j]];
-      i += 2;
-      j += 2;
+  let total = 0;
+  for (let i = 0; i < s.length; i++) {
+    if (regular[s[i]] < regular[s[i + 1]]) {
+      total -= regular[s[i]];
     } else {
-      count += regular[s[i]];
-      i++;
-      j++;
+      total += regular[s[i]];
     }
   }
 
-  return count;
+  return total;
 };
 
-// console.log(romanToInt("III"));
-// console.log(romanToInt("LVIII"));
-console.log(romanToInt("MCMXCIV"));
+// const special = {
+//   IV: 4,
+//   IX: 9,
+//   XL: 40,
+//   XC: 90,
+//   CD: 400,
+//   CM: 900,
+// };
+
+// var romanToInt = function(s) {
+//     let total = 0;
+//     let i = 0;
+//     while (i < s.length) {
+//         const temp = s[i] + s[i + 1];
+//         if (temp in special) {
+//             total += special[temp];
+//             i += 2;
+//         } else {
+//             total += regular[s[i]]
+//             i++;
+//         }
+//     }
+//     return total;
+// };
+
+// TRASH vvvvv
+// const regular = {
+//   I: 1,
+//   V: 5,
+//   X: 10,
+//   L: 50,
+//   C: 100,
+//   D: 500,
+//   M: 1000,
+// };
+
+// const special = {
+//   IV: 4,
+//   IX: 9,
+//   XL: 40,
+//   XC: 90,
+//   CD: 400,
+//   CM: 900,
+// };
+
+// var romanToInt = function (s) {
+//   let i = 0,
+//     j = 1;
+//   let count = 0;
+//   while (i < s.length) {
+//     if (s[i] + s[j] in special) {
+//       console.log(s[i] + s[j]);
+//       count += special[s[i] + s[j]];
+//       i += 2;
+//       j += 2;
+//     } else {
+//       count += regular[s[i]];
+//       i++;
+//       j++;
+//     }
+//   }
+
+//   return count;
+// };
+
+// // console.log(romanToInt("III"));
+// // console.log(romanToInt("LVIII"));
+// console.log(romanToInt("MCMXCIV"));