Added javascript solution for 13. Roman to Integer

javascript/13-Roman-to-Integer.js

@@ -0,0 +1,65 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var romanToInt = function (s) {
+ let romans = {
+ I: 1,
+ V: 5,
+ X: 10,
+ L: 50,
+ C: 100,
+ D: 500,
+ M: 1000,
+ };
+
+ let arr = s.split("");
+
+ let sum = 0;
+
+ for (let i = arr.length - 1; i >= 0; i--) {
+ // IV : 4
+ if (romans[arr[i]] === romans["V"]) {
+ if (romans[arr[i - 1]] === romans["I"]) {
+ sum -= 1 * 2;
+ }
+ }
+ // IX : 4
+ if (romans[arr[i]] === romans["X"]) {
+ if (romans[arr[i - 1]] === romans["I"]) {
+ sum -= 1 * 2;
+ }
+ }
+ // XL : 40
+ if (romans[arr[i]] === romans["L"]) {
+ if (romans[arr[i - 1]] === romans["X"]) {
+ sum -= 10 * 2;
+ }
+ }
+ // XC : 90
+ if (romans[arr[i]] === romans["C"]) {
+ if (romans[arr[i - 1]] === romans["X"]) {
+ sum -= 10 * 2;
+ }
+ }
+ // CD : 400
+ if (romans[arr[i]] === romans["D"]) {
+ if (romans[arr[i - 1]] === romans["C"]) {
+ sum -= 100 * 2;
+ }
+ }
+ // CM : 900
+ if (romans[arr[i]] === romans["M"]) {
+ if (romans[arr[i - 1]] === romans["C"]) {
+ sum -= 100 * 2;
+ }
+ }
+
+ sum += romans[arr[i]];
+ }
+
+ return sum;
+};
+
+// Runtime: 148 ms, faster than 80.16% of JavaScript online submissions for Roman to Integer.
+// Memory Usage: 47.5 MB, less than 18.15% of JavaScript online submissions for Roman to Integer.