codewars练习（javascript）-2021/2/2

codewars-js练习

2021/2/2

github 地址

my github地址，上面有做的习题记录，不断更新…

【1】<7kyu>【You’re a square!】

Given an integral number, determine if it’s a square number:

example：

-1  =>  false
 0  =>  true
 3  =>  false
 4  =>  true
25  =>  true
26  =>  false

solution

<script type="text/javascript">
 		var isSquare = function(n){
 			console.log(n);
 			let i = 0;
 			if(n!=0){
 				while (n > i * i) {
					i++;
				}
				return i * i === n;
 			}
 			return true;
 		}

 		// 验证
		console.log(isSquare(-1));// false
		console.log(isSquare(25));//true
		console.log(isSquare(0));//false
	</script>

【2】<7kyu>【Find the next perfect square!】

You might know some pretty large perfect squares. But what about the NEXT one?

Complete the findNextSquare method that finds the next integral perfect square after the one passed as a parameter. Recall that an integral perfect square is an integer n such that sqrt(n) is also an integer.

If the parameter is itself not a perfect square then -1 should be returned. You may assume the parameter is positive.

找下一个完全平方数

example：

findNextSquare(121) --> returns 144
findNextSquare(625) --> returns 676
findNextSquare(114) --> returns -1 since 114 is not a perfect

solution

<script type="text/javascript">
 		function findNextSquare(sq) {
 			// console.log(sq);
			for(var i=0;i>-1;i++){
				var square = i*i;
        		if(square==sq){
        			// console.log('i',i);
        			return (i+1)*(i+1);
        		}else if(square>sq){
        			return -1;
        		} 
			}
 		}

 		// 验证
		console.log(findNextSquare(121));// 144
		console.log(findNextSquare(625));// 676
		console.log(findNextSquare(114));// -1
	</script>

【3】<7kyu>【Predict your age!】

In honor of my grandfather’s memory we will write a function using his formula!

• Take a list of ages when each of your great-grandparent died.
• Multiply each number by itself.
• Add them all together.
• Take the square root of the result.
• Divide by two.

列出你曾祖父去世时的年龄。把每个数单独乘起来。把它们加在一起。对结果开平方根。除以2。

example：

predictAge(65, 60, 75, 55, 60, 63, 64, 45) === 86

solution

<script type="text/javascript">
 		function predictAge(age1,age2,age3,age4,age5,age6,age7,age8){
 			let arr = [age1,age2,age3,age4,age5,age6,age7,age8];
 			console.log(arr);
 			let sum = 0;
 			for(var i=0;i<arr.length;i++){
 				sum +=(arr[i] * arr[i]);
 			}
 			return Math.floor(Math.sqrt(sum)/2);
 		}

 		// 验证
		console.log(predictAge(65, 60, 75, 55, 60, 63, 64, 45));// 86
	</script>

以上为自己思路供大家参考，可能有更优的思路。