sqrt_binary_search.go

// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package sqrt

func sqrtBinSearch(n int64) float64 {
	low, high := float64(1), float64(n)
	for n := float64(n); ; {
		mid := (high + low) / 2

		switch squared := mid * mid; {
		case squared == n:
			return mid
		case squared < n:
			low = mid
		case squared > n:
			high = mid
		}

		if low+precision > high {
			return mid
		}
	}
}