From f887a8f8f9a332e083a2aa8d3c4be99e8682c1c9 Mon Sep 17 00:00:00 2001
From: chayan das <110921638+Chayandas07@users.noreply.github.com>
Date: Sun, 14 Jul 2024 21:07:21 +0530
Subject: [PATCH] Create 726. Number of Atoms

---
 726. Number of Atoms | 52 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 726. Number of Atoms

diff --git a/726. Number of Atoms b/726. Number of Atoms
new file mode 100644
index 0000000..aaf5aa4
--- /dev/null
+++ b/726. Number of Atoms	
@@ -0,0 +1,52 @@
+
+
+class Solution {
+public:
+    string countOfAtoms(string formula) {
+        stack<map<string, int>> stk;
+        stk.push(map<string, int>());
+        int n = formula.size();
+        for (int i = 0; i < n;) {
+            if (formula[i] == '(') {
+                stk.push(map<string, int>());
+                i++;
+            } else if (formula[i] == ')') {
+                auto top = stk.top();
+                stk.pop();
+                i++;
+                int i_start = i;
+                while (i < n && isdigit(formula[i])) {
+                    i++;
+                }
+                int multiplier = i > i_start ? stoi(formula.substr(i_start, i - i_start)) : 1;
+                for (auto &p : top) {
+                    stk.top()[p.first] += p.second * multiplier;
+                }
+            } else {
+                int i_start = i;
+                i++;
+                while (i < n && islower(formula[i])) {
+                    i++;
+                }
+                string element = formula.substr(i_start, i - i_start);
+                i_start = i;
+                while (i < n && isdigit(formula[i])) {
+                    i++;
+                }
+                int count = i > i_start ? stoi(formula.substr(i_start, i - i_start)) : 1;
+                stk.top()[element] += count;
+            }
+        }
+        auto &counts = stk.top();
+        vector<pair<string, int>> elements(counts.begin(), counts.end());
+        sort(elements.begin(), elements.end());
+        string result;
+        for (auto &p : elements) {
+            result += p.first;
+            if (p.second > 1) {
+                result += to_string(p.second);
+            }
+        }
+        return result;
+    }
+};