在二进制搜索中找到目标时的猜测总数

Total number of guesses when it has found the target in Binary seach

本文关键字：目标 搜索 二进制      更新时间：2024-06-30

这是请求为了帮助可视化搜索所需的时间，请添加一个println（）语句，该语句显示查找结果所需的猜测总数。

当函数找到目标时，它应该只打印猜测的总数。您的函数不应该打印每个循环的猜测次数。

注意：二进制搜索数组素数上的目标值41需要1个猜测。

我的代码

var doSearch = function(array, targetValue) {
	var min = 0;
	var max = array.length - 1;
    var guess;
    var count = 0;
    while(min <= max) {
        guess = Math.floor((max + min)/2);
        count ++;
        if(array[guess] === targetValue) {
            println(guess);
            println(count ++);
            return guess;
        }
        //again
        else if (targetValue < array[guess]){
        max = guess - 1;
        } 
        else {
        min = guess + 1;
        }
    }
    
	return -1;
};
var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];
var result = doSearch(primes, 73);
println("Found prime at index " + result);
Program.assertEqual(doSearch(primes, 73), 20);

通知仍然错误看起来您正在增加每个子句中的猜测次数。试着在一个地方增加猜测的次数。

我做错了什么？

// Full answer
var doSearch = function(array, targetValue) {
    var min = 0;
    var max = array.length - 1;
    var guess;
    var count = 0;
    while (max >= min) {
        guess = Math.floor((max + min)/2);
        count++;
        if (array[guess] === targetValue) {
            println(guess);
            println(count);
            return guess;
        
        }
        else if (array[guess] < targetValue) {
            min = guess + 1;
            println(array[guess]);
        }
        else {
            max = guess - 1;
            println(array[guess]);
        }
    }
            

    return -1;
};
var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
    41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];
var result = doSearch(primes, 73);
println("Found prime at index " + result);
Program.assertEqual(doSearch(primes, 73), 20);
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