From 4a6e21dafb7785bb0f373e20d3286a4db762a594 Mon Sep 17 00:00:00 2001
From: Pgodwin1 <pgodwin287@gmail.com>
Date: Tue, 8 Aug 2023 14:38:05 +0100
Subject: [PATCH] my first commit

---
 src/brackets/index.js       | 19 ++++++++++++++++++-
 src/roman-numerals/index.js | 25 ++++++++++++++++++++++++-
 src/transpose/index.js      | 16 +++++++++++++++-
 3 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/src/brackets/index.js b/src/brackets/index.js
index 96b6766..a36bdd7 100644
--- a/src/brackets/index.js
+++ b/src/brackets/index.js
@@ -4,6 +4,23 @@
  * @param {string} str The string of brackets.
  * @returns {"valid" | "invalid"} Whether or not the string is valid.
  */
-function isValid(str) {}
+function isValid(str) {
+    const stack = [];
+    const open = "({[";
+    const close = ")}]";
+
+    for(let char of str) {
+        if(open.includes(char)) {
+            stack.push(char);
+        } else if(close.includes(char)) {
+            const lastOpenBracket = stack.pop();
+            if(!lastOpenBracket || open.indexOf(lastOpenBracket) !== close.indexOf(char)) {
+                return "invalid";
+            }
+        }  
+    }
+    return stack.length === 0 ? "valid" : "invalid";
+}
+
 
 module.exports = isValid;
diff --git a/src/roman-numerals/index.js b/src/roman-numerals/index.js
index 38afb19..4c5b753 100644
--- a/src/roman-numerals/index.js
+++ b/src/roman-numerals/index.js
@@ -4,6 +4,29 @@
  * @param {string} roman The all-caps Roman numeral between 1 and 3999 (inclusive).
  * @returns {number} The decimal equivalent.
  */
-function romanToDecimal(roman) {}
+function romanToDecimal(roman) {
+    let numeral = new Map();
+
+    numeral.set('I', 1);
+    numeral.set('V', 5);
+    numeral.set('X', 10);
+    numeral.set('L', 50);
+    numeral.set('C', 100);
+    numeral.set('D', 500);
+    numeral.set('M', 1000);
+  
+    let decimal = 0;
+  for(let i = 0; i < roman.length; i++) {
+       const numeralSymbol = numeral.get(roman[i]);
+       const nextNumeralSymbol = (i + 1 < roman.length) ? numeral.get(roman[i + 1]) : 0;
+
+       if(numeralSymbol < nextNumeralSymbol) {
+                 decimal -= numeralSymbol;
+       } else {
+                 decimal += numeralSymbol;
+       }
+  }
+  return decimal;
+}
 
 module.exports = romanToDecimal;
diff --git a/src/transpose/index.js b/src/transpose/index.js
index adec201..7502b70 100644
--- a/src/transpose/index.js
+++ b/src/transpose/index.js
@@ -4,6 +4,20 @@
  * @param {number[]} array The array to transpose
  * @returns {number[]} The transposed array
  */
-function transpose(array) {}
+function transpose(array) {
+    let rows = array.length;
+    let cols = array[0].length;
+
+    let transposedMatrix = [];
+    for(let c = 0; c < cols; c++) {
+        transposedMatrix[c] = Array(rows);
+    }
+    for(let r = 0; r < rows; r++) {
+        for(let c = 0; c < cols; c++) {
+            transposedMatrix[c][r] = array[r][c];
+        }
+    }
+    return transposedMatrix;
+}
 
 module.exports = transpose;