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-rw-r--r--basic_calculator.cpp37
1 files changed, 37 insertions, 0 deletions
diff --git a/basic_calculator.cpp b/basic_calculator.cpp
new file mode 100644
index 0000000..80e0ffe
--- /dev/null
+++ b/basic_calculator.cpp
@@ -0,0 +1,37 @@
+#include "leetcode.h"
+
+class Solution {
+public:
+ int calculate(string s) {
+ stack<pair<int, int>> sp;
+ long long int ans = 0;
+ int sign = +1;
+ for (int i = 0; i < s.size(); ++i) {
+ char ch = s[i];
+ if (isdigit(ch)) {
+ long long int num = 0;
+ while (i < s.size() && isdigit(s[i])) {
+ num = (num * 10) + s[i] - '0';
+ i++;
+ }
+ i--;
+ ans += (num * sign);
+ sign = +1;
+ } else if (ch == '(') {
+ sp.push(make_pair(ans, sign));
+ ans = 0;
+ sign = +1;
+ } else if (ch == ')') {
+ ans = sp.top().first + (sp.top().second * ans);
+ sp.pop();
+ } else if (ch == '-')
+ sign = (-1 * sign);
+ }
+ return ans;
+ }
+};
+
+int main() {
+ Solution obj;
+ cout << obj.calculate("1 + 1");
+}