added debug

debug.h

@@ -0,0 +1,112 @@
+#include <bits/stdc++.h>
+namespace __DEBUG_UTIL__
+{
+    using namespace std;
+    template <typename T>
+    concept is_iterable = requires(T &&x) { begin(x); } &&
+                          !is_same_v<remove_cvref_t<T>, string>;
+    void print(const char *x) { cerr << x; }
+    void print(char x) { cerr << "\'" << x << "\'"; }
+    void print(bool x) { cerr << (x ? "T" : "F"); }
+    void print(string x) { cerr << "\"" << x << "\""; }
+    void print(vector<bool> &v)
+    { /* Overloaded this because stl optimizes vector<bool> by using
+         _Bit_reference instead of bool to conserve space. */
+        int f = 0;
+        cerr << '{';
+        for (auto &&i : v)
+            cerr << (f++ ? "," : "") << (i ? "T" : "F");
+        cerr << "}";
+    }
+    template <typename T>
+    void print(T &&x)
+    {
+        if constexpr (is_iterable<T>)
+            if (size(x) && is_iterable<decltype(*(begin(x)))>)
+            { /* Iterable inside Iterable */
+                int f = 0;
+                cerr << "\n~~~~~\n";
+                for (auto &&i : x)
+                {
+                    cerr << setw(2) << left << f++, print(i), cerr << "\n";
+                }
+                cerr << "~~~~~\n";
+            }
+            else
+            { /* Normal Iterable */
+                int f = 0;
+                cerr << "{";
+                for (auto &&i : x)
+                    cerr << (f++ ? "," : ""), print(i);
+                cerr << "}";
+            }
+        else if constexpr (requires { x.pop(); }) /* Stacks, Priority Queues, Queues */
+        {
+            auto temp = x;
+            int f = 0;
+            cerr << "{";
+            if constexpr (requires { x.top(); })
+                while (!temp.empty())
+                    cerr << (f++ ? "," : ""), print(temp.top()), temp.pop();
+            else
+                while (!temp.empty())
+                    cerr << (f++ ? "," : ""), print(temp.front()), temp.pop();
+            cerr << "}";
+        }
+        else if constexpr (requires { x.first; x.second; }) /* Pair */
+        {
+            cerr << '(', print(x.first), cerr << ',', print(x.second), cerr << ')';
+        }
+        else if constexpr (requires { get<0>(x); }) /* Tuple */
+        {
+            int f = 0;
+            cerr << '(', apply([&f](auto... args)
+                               { ((cerr << (f++ ? "," : ""), print(args)), ...); },
+                               x);
+            cerr << ')';
+        }
+        else
+            cerr << x;
+    }
+    template <typename T, typename... V>
+    void printer(const char *names, T &&head, V &&...tail)
+    {
+        int i = 0;
+        for (size_t bracket = 0; names[i] != '\0' and (names[i] != ',' or bracket != 0); i++)
+            if (names[i] == '(' or names[i] == '<' or names[i] == '{')
+                bracket++;
+            else if (names[i] == ')' or names[i] == '>' or names[i] == '}')
+                bracket--;
+        cerr.write(names, i) << " = ";
+        print(head);
+        if constexpr (sizeof...(tail))
+            cerr << " ||", printer(names + i + 1, tail...);
+        else
+            cerr << "]\n";
+    }
+    template <typename T, typename... V>
+    void printerArr(const char *names, T arr[], size_t N, V... tail)
+    {
+        size_t i = 0;
+        for (; names[i] and names[i] != ','; i++)
+            cerr << names[i];
+        for (i++; names[i] and names[i] != ','; i++)
+            ;
+        cerr << " = {";
+        for (size_t ind = 0; ind < N; ind++)
+            cerr << (ind ? "," : ""), print(arr[ind]);
+        cerr << "}";
+        if constexpr (sizeof...(tail))
+            cerr << " ||", printerArr(names + i + 1, tail...);
+        else
+            cerr << "]\n";
+    }
+
+}
+#ifdef ONLINE_JUDGE
+#define dbg(...)
+#define dbgArr(...)
+#else
+#define dbg(...) std::cerr << __LINE__ << ": [", __DEBUG_UTIL__::printer(#__VA_ARGS__, __VA_ARGS__)
+#define dbgArr(...) std::cerr << __LINE__ << ": [", __DEBUG_UTIL__::printerArr(#__VA_ARGS__, __VA_ARGS__)
+#endif