【数据结构与算法】什么是时间复杂度和空间复杂度？

void sayHello(String name){
    System.out.prinln("Hello, " + String);
    System.out.prinln("欢迎关注我的公众号：【村雨遥】");
}

int binarySearch(int[] arr, int target){
    int left = 0;
    int right = arr.length - 1;
    while(left <= right){
        int middle = left + (left - right) / 2;
        if(arr[middle] == target){
            return middle;
        }else if(arr[middle] > target){
            right = middle - 1;
        }else {
            left = middle + 1;
        }
    }

    return -1;
}

int sum(int[] arr){
    int total = 0;

    for(int i = 0; i < arr.length; i++){
        total += arr[i];
    }

    return total;
}

void hello (int n){
    for( int i = 1 ; i < n ; i++){
        int m = 1;
        while( m < n ){
            m *= 2;
        }
    }
}

void selectionSort(int[] arr, int n){
    for(int i = 0; i < n; i++){
        int min = i;
        for(int j = i + 1; j < n; j++){
            if(arr[j] < arr[min]){
                int tmp = arr[i];
                arr[i] = arr[j];
                arr[j] = tmp;
            }
        }
    }
}

void demo(int n){
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            for(int k = 0; k < n; k++){
                System.out.print("Hello, World");
            }
            System.out.print("------");
        }
        System.out.print("******");
    }
}

int num1 = 1;
int num2 = 2;
int total = num1 + num2;

int[] arr = new int[n];

int[][] arr = new int[n][n];