clang-format and clang-tidy fixes for e09a0579

math/ncr_modulo_p.cpp

@@ -2,109 +2,108 @@
  * @file
  * @brief This program aims at calculating nCr modulo p
  * @details nCr is defined as n! / (r! * (n-r)!) where n! represents factorial
- * of n. In many cases, the value of nCr is too large to fit in a 64 bit integer.
- * Hence, in competitive programming, there are many problems or subproblems
- * to compute nCr modulo p where p is a given number.
+ * of n. In many cases, the value of nCr is too large to fit in a 64 bit
+ * integer. Hence, in competitive programming, there are many problems or
+ * subproblems to compute nCr modulo p where p is a given number.
  * @author [Kaustubh Damania](https://github.com/KaustubhDamania)
  */
 
- #include <cassert>  /// for assert
- #include <iostream> /// for io operations
- #include <vector>   /// for std::vector
+#include <cassert>   /// for assert
+#include <iostream>  /// for io operations
+#include <vector>    /// for std::vector
 
+/**
+ * @namespace math
+ * @brief Mathematical algorithms
+ */
+namespace math {
+/**
+ * @brief Class which contains all methods required for calculating nCr mod p
+ */
+class NCRModuloP {
+ private:
+    std::vector<uint64_t> fac;
+    uint64_t p;
 
- /**
-  * @namespace math
-  * @brief Mathematical algorithms
-  */
- namespace math {
-     /**
-     * @brief Class which contains all methods required for calculating nCr mod p
+ public:
+    /** Constructor which precomputes the values of n! % mod from n=0 to size
+     *  and stores them in vector 'fac'
+     *  @params[in] the numbers 'size', 'mod'
      */
-    class NCRModuloP {
-    private:
-        std::vector<uint64_t> fac;
-        uint64_t p;
-    public:
-        /** Constructor which precomputes the values of n! % mod from n=0 to size
-         *  and stores them in vector 'fac'
-         *  @params[in] the numbers 'size', 'mod'
-        */
-        NCRModuloP(uint64_t size, uint64_t mod){
-            p = mod;
-            fac = std::vector<uint64_t>(size);
-            fac[0] = 1;
-            for (int i = 1; i <= size; i++) {
-                fac[i] = (fac[i - 1] * i) % p;
-            }
+    NCRModuloP(uint64_t size, uint64_t mod) {
+        p = mod;
+        fac = std::vector<uint64_t>(size);
+        fac[0] = 1;
+        for (int i = 1; i <= size; i++) {
+            fac[i] = (fac[i - 1] * i) % p;
+        }
+    }
+
+    /** Finds the value of x, y such that a*x + b*y = gcd(a,b)
+     *
+     * @params[in] the numbers 'a', 'b' and address of 'x' and 'y' from above
+     * equation
+     * @returns the gcd of a and b
+     */
+    uint64_t gcdExtended(uint64_t a, uint64_t b, int64_t *x, int64_t *y) {
+        if (a == 0) {
+            *x = 0, *y = 1;
+            return b;
         }
 
-        /** Finds the value of x, y such that a*x + b*y = gcd(a,b)
-         *
-         * @params[in] the numbers 'a', 'b' and address of 'x' and 'y' from above
-         * equation
-         * @returns the gcd of a and b
-         */
-        uint64_t gcdExtended(uint64_t a, uint64_t b, int64_t *x, int64_t *y) {
-            if (a == 0) {
-                *x = 0, *y = 1;
-                return b;
-            }
+        int64_t x1 = 0, y1 = 0;
+        uint64_t gcd = gcdExtended(b % a, a, &x1, &y1);
 
-            int64_t x1 = 0, y1 = 0;
-            uint64_t gcd = gcdExtended(b % a, a, &x1, &y1);
+        *x = y1 - (b / a) * x1;
+        *y = x1;
+        return gcd;
+    }
 
-            *x = y1 - (b / a) * x1;
-            *y = x1;
-            return gcd;
+    /** Find modular inverse of a with m i.e. a number x such that (a*x)%m = 1
+     *
+     * @params[in] the numbers 'a' and 'm' from above equation
+     * @returns the modular inverse of a
+     */
+    int64_t modInverse(uint64_t a, uint64_t m) {
+        int64_t x = 0, y = 0;
+        uint64_t g = gcdExtended(a, m, &x, &y);
+        if (g != 1) {  // modular inverse doesn't exist
+            return -1;
+        } else {
+            int64_t res = ((x + m) % m);
+            return res;
         }
+    }
 
-        /** Find modular inverse of a with m i.e. a number x such that (a*x)%m = 1
-         *
-         * @params[in] the numbers 'a' and 'm' from above equation
-         * @returns the modular inverse of a
-         */
-        int64_t modInverse(uint64_t a, uint64_t m) {
-            int64_t x = 0, y = 0;
-            uint64_t g = gcdExtended(a, m, &x, &y);
-            if (g != 1) {  // modular inverse doesn't exist
-                return -1;
-            }
-            else {
-                int64_t res = ((x + m) % m);
-                return res;
-            }
+    /** Find nCr % p
+     *
+     * @params[in] the numbers 'n', 'r' and 'p'
+     * @returns the value nCr % p
+     */
+    int64_t ncr(uint64_t n, uint64_t r, uint64_t p) {
+        // Base cases
+        if (r > n) {
+            return 0;
         }
-
-        /** Find nCr % p
-         *
-         * @params[in] the numbers 'n', 'r' and 'p'
-         * @returns the value nCr % p
-         */
-        int64_t ncr(uint64_t n, uint64_t r, uint64_t p) {
-            // Base cases
-            if (r > n) {
-                return 0;
-            }
-            if (r == 1) {
-                return n % p;
-            }
-            if (r == 0 || r == n){
-                return 1;
-            }
-            // fac is a global array with fac[r] = (r! % p)
-            int64_t denominator = modInverse(fac[r], p);
-            if (denominator < 0) {  // modular inverse doesn't exist
-                return -1;
-            }
-            denominator = (denominator * modInverse(fac[n - r], p)) % p;
-            if (denominator < 0) {  // modular inverse doesn't exist
-                return -1;
-            }
-            return (fac[n] * denominator) % p;
+        if (r == 1) {
+            return n % p;
         }
-    };
-} // namespace math
+        if (r == 0 || r == n) {
+            return 1;
+        }
+        // fac is a global array with fac[r] = (r! % p)
+        int64_t denominator = modInverse(fac[r], p);
+        if (denominator < 0) {  // modular inverse doesn't exist
+            return -1;
+        }
+        denominator = (denominator * modInverse(fac[n - r], p)) % p;
+        if (denominator < 0) {  // modular inverse doesn't exist
+            return -1;
+        }
+        return (fac[n] * denominator) % p;
+    }
+};
+}  // namespace math
 
 /**
  * @brief Test implementations
@@ -116,12 +115,11 @@ void tests(math::NCRModuloP ncrObj) {
     // (52323 C 26161) % (1e9 + 7) = 224944353
     assert(ncrObj.ncr(52323, 26161, 1000000007) == 224944353);
     // 6 C 2 = 30, 30%5 = 0
-    assert(ncrObj.ncr(6,2,5) == 0);
+    assert(ncrObj.ncr(6, 2, 5) == 0);
     // 7C3 = 35, 35 % 29 = 8
-    assert(ncrObj.ncr(7,3,29) == 6);
+    assert(ncrObj.ncr(7, 3, 29) == 6);
 }
 
-
 /**
  * @brief Main function
  * @returns 0 on exit
@@ -135,6 +133,6 @@ int main() {
     for (int i = 0; i <= 7; i++) {
         std::cout << 6 << "C" << i << " = " << ncrObj.ncr(6, i, p) << "\n";
     }
-    tests(ncrObj); // execute the tests
+    tests(ncrObj);  // execute the tests
     std::cout << "Assertions passed\n";
 }