Solved Day04 q001

Problems/Data-structures/Day-04/sol/Satwik/Solution1.cpp

@@ -0,0 +1,70 @@
+/*
+Problem: find the minimum cost after replace each _ by brackets which follow RBS
+
+Approach:
+Use a stack which hold index for '(' or '_' if stack is empty.
+'_' = '(' - if empty stack.
+'_' = ')' - if not empty.
+
+Complexity:
+Time: O(n)
+Space: O(n): for the stack.
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define vll vector<ll>
+#define out(x) cout << (x) << endl
+#define outr(x)            \
+    {                      \
+        cout << x << endl; \
+        return;            \
+    }
+
+void solve()
+{
+    ll n;
+    cin >> n;
+    string s;
+    cin >> s;
+
+    ll res = 0;
+    stack<ll> st;
+    for (ll i = 0; i < n; i++)
+    {
+        if (s[i] == '(')
+            st.push(i);
+        else if (s[i] == '_')
+        {
+            if (st.empty())
+            {
+                st.push(i);
+            }
+            else
+            {
+                res += (i - st.top());
+                st.pop();
+            }
+        }
+        else
+        {
+            res += (i - st.top());
+            st.pop();
+        }
+    }
+
+    out(res);
+}
+
+int main()
+{
+    ll t;
+    cin >> t;
+    while (t--)
+    {
+        solve();
+    }
+}
+
+//submission link: https://codeforces.com/problemset/submission/1997/355793929