[数据结构与算法]LeetCode && AcWing

Author:龙箬
Data Science and Big Data Technology
Change the world with data!
CSDN@weixin_43975035
算法刷题，坚持下去，就是胜利

LeetCode

两数之和

代码如下：

public class TwoSum {
    public int[] twoSum(int[] nums,int target){
        int i,j;
        int [] array=new int[2];
        for (i=0;i<nums.length-1;i++){
            for (j=i+1;j<nums.length;j++){
                if (nums[i]+nums[j]==target) {
                    array[0] = i;
                    array[1] = j;
                }
            }
        }
        return array;
    }
    public static void main(String[] args){
        TwoSum heap=new TwoSum();
        int[] a={2,8,7,15};
        int[] arr=heap.twoSum(a,9);
        int i;
        for (i=0;i<arr.length;i++){
            System.out.println(arr[i]);
        }
    }
}

删除排序数组中的重复项

代码如下：

import java.util.Arrays;

public class removeDuplicates {
    public static int[] nums={0,1,1,2,7,4,4,5,4};
    public static void main(String[] args){
        Arrays.sort(nums);
        removeDuplicates(nums);
    }

    public static void removeDuplicates(int[] nums){
        int i=0;
        for(int j=1;j<nums.length;j++){
            if(nums[j]!=nums[i]){
                i++;
                nums[i]=nums[j];
            }
        }
        System.err.print((i+1)+", nums = [");
        for (int k=0;k<i;k++){
            System.out.print(nums[k]+",");
        }
        System.out.print(nums[i]+"]");
    }
}

AcWing

A + B

代码如下：

import java.util.Scanner;

public class AcWing01 {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        int b=sc.nextInt();
        int sum=a+b;
        System.out.print(sum);
    }
}

01背包问题

代码如下：

import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner input=new Scanner(System.in);
        int N=input.nextInt();
        int V=input.nextInt();
        int[] weight=new int[N];
        int[] value=new int[N];
        for (int i=0;i<N;i++){
            weight[i]=input.nextInt();
            value[i]=input.nextInt();
        }
        int[][] backpacks=new int[N+1][V+1];
        for (int i=1;i<=N;i++){
            for (int j=1;j<=V;j++){
                backpacks[i][j]=backpacks[i-1][j];
                if (j>=weight[i-1]){
                    backpacks[i][j]=Math.max(backpacks[i-1][j],backpacks[i-1][j-weight[i-1]]+value[i-1]);
                }
            }
        }
        System.out.print(backpacks[N][V]);
    }
}

二进制中1的个数

代码如下：

class Solution {
    public static int NumberOf1(int n){
        char[] chs=Integer.toBinaryString(n).toCharArray();
        int res=0;
        for (int i=0;i<chs.length;i++){
            if (chs[i]=='1'){
                res++;
            }
        }
        return res;
    }
    
    public static void main(String[] args){
        Scanner sca=new Scanner(System.in);
        int n=sca.nextInt();
        NumberOf1(n);
    }
}

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代码如有错误，欢迎留言批评改正。