add new solutions

solutions/16/q1680/solution.go

@@ -0,0 +1,20 @@
+// Package q1680 implements a solution for https://leetcode.com/problems/concatenation-of-consecutive-binary-numbers/
+package q1680
+
+const MOD int = 1e9 + 7
+
+func concatenatedBinary(n int) int {
+	ret := 0
+	binLen := 1
+
+	for c := 1; c <= n; c++ {
+		if 1<<binLen <= c {
+			binLen++
+		}
+
+		ret = (ret<<binLen + c) % MOD
+	}
+	return ret
+}
+
+var _ = concatenatedBinary