added solution to the problem 1963 of leetcode

leetcode/src/1963.c

@@ -0,0 +1,39 @@
+// Time complexity: O(n)
+// Space complexity: O(1)
+
+int minSwaps(char* s)
+{
+    int n = strlen(s);
+    int sum = 0;
+    int minmSum = INT_MAX;
+
+    for (int i = 0; i < n; i++)
+    {
+        if (s[i] == '[')
+        {
+            // if opening bracket comes increase the sum
+            sum = sum + 1;
+        }
+        else
+        {
+            sum = sum - 1;
+            // in case of closing bracket decrease the sum
+        }
+
+        // find the minimum sum
+        if (sum < minmSum)
+        {
+            minmSum = sum;
+        }
+    }
+    // if minimum sum is greater than 0 then no need of swap
+    // in one swap we can increase the minimum swap by 2
+    if (minmSum > 0)
+    {
+        return 0;
+    }
+    else
+    {
+        return (abs(minmSum) + 1) / 2;
+    }
+}