📐算法_排序算法

一.排序算法🔍

1️⃣. 快速排序 ⚡

class Solution {
    //快速排序
    public int[] sortArray(int[] nums) {
        quickSort(nums,0,nums.length-1);
        return nums;
    }

    public void quickSort(int[] nums,int l,int r){
        if(l<r){
            int pos = random_par(nums,l,r);
            quickSort(nums,l,pos-1);
            quickSort(nums,pos,r);
        }
    }
    public int random_par(int[] nums,int l,int r){
        int t = new Random().nextInt(r-l+1)+l;
        swap(nums,t,r);
        return par(nums,l,r);
    }


    public int par(int[] nums,int l,int r){

        int pv = nums[r];

        int i = l-1;

        for(int j=l;j<r;++j){
            if(nums[j]<=pv){
                i++;
                swap(nums,i,j);
            }
        }

        swap(nums,i+1,r);

        return (i+1);

    }


    public void swap(int[] nums,int l,int r){
        int t = nums[l];
        nums[l]=nums[r];
        nums[r]=t;
    }
}

2️⃣. 堆排序🚀

class Solution {
    //堆排序
    public int[] sortArray(int[] nums) {
        heapSort(nums);
        return nums;
    }

    public void heapSort(int[] nums){
        int len = nums.length-1;

        buildHeap(nums, len);

        for (int i = len; i >= 1; --i) {
            swap(nums, i, 0);
            len -= 1;
            rebuildHeap(nums, 0, len);
        }

    }

    public void buildHeap(int[] nums,int len){
         for (int i = len / 2; i >= 0; --i) {
            rebuildHeap(nums, i, len);
        }

    }

    public void rebuildHeap(int[] nums,int i,int len){
        
          for (; (i << 1) + 1 <= len;) {
            int lson = (i << 1) + 1;
            int rson = (i << 1) + 2;
            int large;
            if (lson <= len && nums[lson] > nums[i]) {
                large = lson;
            } else {
                large = i;
            }
            if (rson <= len && nums[rson] > nums[large]) {
                large = rson;
            }
            if (large != i) {
                swap(nums, i, large);
                i = large;
            } else {
                break;
            }
        }


    }

    public void swap(int[]nums,int l,int r){
        int t = nums[l];
        nums[l]=nums[r];
        nums[r]=t;
    }
}

3️⃣. 归并排序💦

class Solution {

    int[] temp;

    public int[] sortArray(int[] nums) {
        temp = new int[nums.length];

        mergeSort(nums,0,nums.length-1);

        return nums;
    }

    public void mergeSort(int[]nums,int l,int r){
        if(l<r){

            int mid = l+r>>1;

            mergeSort(nums,l,mid); 

            mergeSort(nums,mid+1,r);

            int count=0;

            int i=l,j=mid+1;

            while(i<=mid&&j<=r){

                if(nums[i]<=nums[j]){
                    temp[count++]=nums[i++];
                }else{
                    temp[count++]=nums[j++];
                }


            } 

             while(i<=mid){
                temp[count++]=nums[i++];
             } 

             while(j<=r){
                temp[count++]=nums[j++];
             }

             for (int k = 0; k < r - l + 1; ++k) {
                nums[k + l] = temp[k];
            }



        }
    }


}

4️⃣. 💥

5️⃣. ❓

6️⃣. ❓

1️⃣2️⃣3️⃣4️⃣5️⃣6️⃣7️⃣8️⃣9️⃣🔟
⚫⚪🟤🟣🔵🟡🔴🟠🟢
🧡💛❤💚💙💜🤎🖤🤍💔
💕💞💓💗💖💘💝💟💌💢
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🈴🈵🈲🚼🅰🅱🆎🆑🅾🆘
⛔🛑📛❌⭕❓💯🔅🔆#️⃣*️⃣
🔶🔸◾◽⬛🔷🔹💭💬🌙🌈🔥
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🎁💎🥇🥈🥉🏅🏆🎮🔊🔉🎹
🎵🎶💰📝📊📌🤝

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