题目:
// btnCount: 最多能看到几个按钮
// total: 总条数
// size: 每页几条
// page: 当前第几页
function f(total, size, page,btnCount=5) {
// show me your code
const arr = [] // 能看到的页码集合
return arr
}
// 在可能的情况下,让page处于正中间
f(100, 10, 1, 5) // ==> [1, 2, 3, 4, 5]
f(100, 10, 7, 5) // ==> [5, 6, 7, 8, 9]
f(100, 10, 2, 5) // ==> [1, 2, 3, 4, 5]
f(100, 10, 5, 5) // ==> [3, 4, 5, 6, 7]
答案:
function f(total, size, page, btnCount) {
// show me your code
let arr = [] // 能看到的页码集合
const pageNum = Math.ceil(total / size)
arr[0] = page - Math.floor(btnCount / 2)
arr[btnCount - 1] = page + Math.floor(btnCount / 2)
if(arr[0] < 1) {
arr = []
for (let i = 1; i <= btnCount; i++) {
arr.push(i)
}
} else if(arr[btnCount - 1] > pageNum) {
arr = []
for (let j = pageNum; j > pageNum - btnCount; j--) {
arr.unshift(j)
}
} else {
arr = []
for (let k = page - Math.floor(btnCount / 2); k <= page + Math.floor(btnCount / 2); k++) {
arr.push(k)
}
}
return arr
}
console.log(f(100, 10, 1, 5)); // [1, 2, 3, 4, 5]
console.log(f(100, 10, 4, 5)); // [2, 3, 4, 5, 6]
console.log(f(100, 10, 6, 5)); // [4, 5, 6, 7, 8]
console.log(f(100, 10, 7, 5)); // [5, 6, 7, 8, 9]
console.log(f(100, 10, 9, 5)); // [6, 7, 8, 9, 10]
console.log('.....................');
console.log(f(111, 10, 2, 7)); // [1, 2, 3, 4, 5, 6, 7]
console.log(f(111, 10, 9, 7)); // [6, 7, 8, 9, 10, 11, 12]
console.log(f(111, 10, 12, 7)); // [6, 7, 8, 9, 10, 11, 12]