Inverse Modulo in O(n)

https://www.youtube.com/watch?v=LE9zBhLap-U

InverseModulo.java

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+/*
+ *  Calculating modulo inverse in O(N)
+ *  http://ideone.com/mlL5F2 
+ *  https://www.youtube.com/watch?v=LE9zBhLap-U
+ */
+
+public class nCr {
+
+    public static int MOD = 1000000007,
+                      MAX = 1000000;
+    public static long[] inv, fact, invFact;
+    public static void main(String[] args) {
+        inv = new long[MAX + 1];
+        fact = new long[MAX + 1];
+        invFact = new long[MAX + 1];
+
+        inv[1] = 1;
+        for(int i = 2; i <= MAX; i++)
+            inv[i] = (MOD -(MOD/i)*inv[MOD%i]%MOD)%MOD;   // i^-1 mod p
+        fact[0] = invFact[0] = 1;
+        for (int i = 1; i <= MAX; i++) {
+            fact[i] = (fact[i-1]*i)%MOD;                    // i! mod p
+            invFact[i] = (invFact[i-1]*inv[i])%MOD;     // (i!)^-1 mod p
+        }
+    }
+
+    public static long _nCr(int n, int r) {
+        return (fact[n]*(invFact[r]*invFact[n-r])%MOD)%MOD;
+    }
+}