Added GCD_length c++ program

Program's_Contributed_By_Contributors/C++_Programs/B_GCD_Length.cpp

@@ -0,0 +1,69 @@
+#include<bits/stdc++.h>
+
+#define pb push_back
+#define mp make_pair 
+#define fr first
+#define sc second
+#define clr(a) memset(a, 0, sizeof(a))
+#define sz(x) x.size()
+#define rep(n) for (ll i = 0; i < n; i++)
+#define repc(i, n) for (ll i = 0; i < n; i++)
+#define FOR(i, x, y) for (int i = x; i < y; i++)
+#define DEC(i, x, y) for (int i = x; i >= y; i--)
+#define all(v) v.begin(), v.end()
+#define min3(a, b, c) min(a, min(b, c))
+#define max3(a, b, c) max(a, max(b, c))
+#define alla(a, n) a, a + n
+
+using namespace std;
+
+// Some typedef's
+typedef long long ll;
+typedef unsigned long long ull;
+typedef pair<ll, ll> ii;
+typedef vector<ll> vi;
+typedef vector<ii> vii;
+
+// Some frequently used functions
+template <typename T>
+T modpow(T base, T exp, T modulus){  
+    base %= modulus;  T result = 1;  
+    while(exp > 0){    
+        if(exp & 1) result = (result * base) % modulus;    
+        base = (base * base) % modulus;    
+        exp >>= 1;  
+    }  
+    return result;
+}
+ll lcm(ll a, ll b) { return (a * (b / __gcd(a, b))); }
+//Repeat,Example,Approach,Code,Testcases,Optimize
+// int overflow, array bounds special cases (n=1?) 
+// do smth instead of nothing and stay organized 
+// WRITE STUFF DOWN DON'T GET STUCK ON ONE APPROACH
+
+// Some constants
+const int inf = 1e9 + 7;
+const double eps = 1e-6;
+const double pi = 1.00 * acos(-1.00);
+
+
+
+void solve(){
+    int a,b,c;
+    cin >> a >> b >> c;
+    // odd + odd = even
+    // even + odd = odd
+    // odd + even = odd
+    // even + even = even;
+    int n,    
+
+}
+
+int main(){
+    ios_base::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL) ;
+    int t;
+    cin >> t;
+    while(t--){
+        solve();
+    }
+}