双层for循环 数组简单排序

let arr = [1, 3, 5, 1, 7, 9, 9]

for (let i = 0; i < arr.length; i++) {
    for (let j = i + 1; j < arr.length; j++) {
        if (arr[i] > arr[j]) {
            let three = arr[i]
            arr[i] = arr[j]
            arr[j] = three
        }
    }
}

console.log('arr: ', arr) // [1, 1, 3, 5, 7, 9, 9]