Given an unsorted array nums
, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]...
.
Example:
(1) Given nums = [1, 5, 1, 1, 6, 4]
, one possible answer is [1, 4, 1, 5, 1, 6]
.
(2) Given nums = [1, 3, 2, 2, 3, 1]
, one possible answer is [2, 3, 1, 3, 1, 2]
.
Note:
You may assume all input has valid answer.
Follow Up:
Can you do it in O(n) time and/or in-place with O(1) extra space?
Credits:
Special thanks to @dietpepsi for adding this problem and creating all test cases
思路一:
这道题给了我们一个无序数组,让我们排序成摆动数组,满足nums[0] < nums[1] > nums[2] < nums[3]...,并给了我们例子。我们可以先给数组排序,然后在做调整。调整的方法是找到数组的中间的数,相当于把有序数组从中间分成两部分,然后从前半段的末尾取一个,在从后半的末尾去一个,这样保证了第一个数小于第二个数,然后从前半段取倒数第二个,从后半段取倒数第二个,这保证了第二个数大于第三个数,且第三个数小于第四个数,以此类推直至都取完
var wiggleSort = function(nums) {
nums.sort(function(a,b){
return a-b;
})
var tmp=nums.concat();
var c=Math.ceil(nums.length/2-1);
var b=nums.length-1
console.log(c,b)
for(var i=0;i<tmp.length;i+=2){
if(c==0 && nums.length%2){//奇数的情况
nums[i]=tmp[0];
return;
}
nums[i]=tmp[c--];
nums[i+1]=tmp[b--];
}
};