给我们一个排序后的整数类型元素和一个整数变量x的数组，任务是从给定的数组中形成对，并计算该对中元素的乘积，并检查计算出的乘积是否小于k。
输入值
int arr[] = {2, 7, 1, 0, 8}, int k = 10输出结果
Count of pairs in a sorted array whose product is less than k are: 7
说明
The pairs that can be formed from the given array are: (2, 7) = 14(greater than k), (2, 1) = 2(less than k), (2, 0) = 0(less than k), (2, 8) = 16(greater than k), (7, 1) = 7(less than k), (7, 0) = 0(less than k), (7, 8) = 56(greater than k), (1, 0) = 0(less than k), (1, 8) = 8(less than k), (0, 8) = 0(less than k). So, the count of pairs with sum less than k are 7.
输入值
int arr[] = {2, 4, 6, 8}, int k = 10输出结果
Count of pairs in a sorted array whose product is less than k are: 1
说明
The pairs that can be formed from the given array are: (2, 4) = 8(less than k), (2, 6) = 12(greater than k), (2, 8) = 16(greater than k), (4, 6) = 24(greater than x), (4, 8) = 32(greater than k), (6, 8) = 48(greater than k). So, the count of pairs with products less than k is 1.
解决给定问题的方法可以有多种，即幼稚方法和有效方法。因此，让我们首先来看一下幼稚的方法。
输入一个整数元素数组并计算数组的大小并将数据传递给函数
声明一个临时变量计数，以存储乘积小于k的对的计数。
从i到0开始循环直到数组大小
在循环内，从j到i + 1开始另一个循环，直到数组大小
在循环内部，将乘积计算为arr [i] * arr [j]，并检查IF product <k，然后将计数加1。
返回计数
打印结果。
输入一个整数元素数组并计算数组的大小并将数据传递给函数
声明一个临时变量数以存储总和小于x的对数。
将arr_0设置为0，将arr_1设置为size-1
从arr_0到arr_1开始FOR循环
在循环内，检查IF arr [arr_0] * arr [arr_1] <x，然后将count设置为count +(arr_1-arr_0)并将arr_0 ++ ELSE递减arr_1 1
返回计数
打印结果。
#include <iostream>
using namespace std;
int pair_product(int arr[], int size, int k){
int count = 0;
int product = 1;
for(int i = 0 ; i<size ; i++){
for(int j = i+1; j<size; j++){
product = arr[i] * arr[j];
if(product < k){
count++;
}
}
}
return count;
}
int main(){
int arr[] = {5, 8, 2, 1, 3};
int size = sizeof(arr) / sizeof(arr[0]);
int k = 10;
cout<<"Count of pairs in a sorted array whose product is less than k are: "<<pair_product(arr, size, k);
return 0;
}输出结果
如果我们运行上面的代码，它将生成以下输出-
Count of pairs in a sorted array whose product is less than k are: 5
#include <iostream>
using namespace std;
int pair_product(int arr[], int size, int k){
int arr_0 = 0;
int arr_1 = size-1;
int count = 0;
int product = 1;
while(arr_0 < arr_1){
product = arr[arr_0] * arr[arr_1];
if (product < k){
count = count + (arr_1 - arr_0);
arr_0++;
}
else{
arr_1--;
}
}
return count;
}
int main(){
int arr[] = {1, 3, 4, 2, 1};
int size = sizeof(arr) / sizeof(arr[0]);
int k = 5;
cout<<"Count of pairs in a sorted array whose product is less than k are: "<<pair_product(arr, size, k);
return 0;
}输出结果
如果我们运行上面的代码，它将生成以下输出-
Count of pairs in a sorted array whose product is less than k are: 10