Solve 224 with C++

Author: illuz

solutions/224.Basic_Calculator/AC_stack_n.cpp

@@ -0,0 +1,50 @@
+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_stack_n.cpp
+*  Create Date: 2015-09-07 19:07:22
+*  Descripton:   
+*/
+
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 0;
+
+class Solution {
+public:
+    int calculate(string s) {
+        stack<int> nums;
+        stack<int> signs;
+        int num = 0, res = 0, sign = 1;
+        for (auto ch : s) {
+            if (ch == ' ') continue;
+            if (isdigit(ch)) {
+                num = num * 10 + (ch - '0');
+            } else {
+                res += num * sign;
+                num = 0;
+                if (ch == '+') sign = 1;
+                if (ch == '-') sign = -1;
+                if (ch == '(') {
+                    nums.push(res);
+                    signs.push(sign);
+                    res = 0;
+                    sign = 1;
+                }
+                if (ch == ')') {
+                    res = nums.top() + res * signs.top();
+                    nums.pop();
+                    signs.pop();
+                }
+            }
+        }
+        res += sign * num;
+        return res;
+    }
+};
+
+int main() {
+
+    return 0;
+}
+