使用 O(n^2) 时间(朴素方法)查找最大子数组和的 C++ 程序
我们将开发一个 C++ 程序来查找最大子数组和 O(n^2) 时间(朴素方法)。
算法
Begin Take the array elements as input. Make a loop for the length of the sub-array from 1 to n, within this loop, Make another loop nested with the previous one, calculate the sum of first sub-array of that length. For remaining sub-array sum, add the next element to the sum and subtract the first element of that sub-array. Compare it with the global max and update if found out to be more. Print the max sub-array and their sum as a result. End.
示例代码
#include<iostream> using namespace std; int main() { int n, i, j, m=-1, s, ini_m, fi_m; cout<<"\nEnter the number of data element in the array: "; cin>>n; int a[n]; for(i = 0; i < n; i++) { cout<<"Enter element "<<i+1<<": "; cin>>a[i]; } for(i = 1; i < n+1; i++) { s = 0; for(j = 0; j < n; j++) { if(j < i) s += a[j]; else s = s+a[j]-a[j-i]; if(m< s) { ini_m = j-i+1; fi_m = j; m = s; } } } cout<<"\nThe maximum sub array is: "; for(i = ini_m; i <= fi_m; i++) cout<<a[i]<<" "; cout<<"\nThe maximum sub-array sum is: "<<m; }
输出
Enter the number of data element in the array: 10 Enter element 1: 1 Enter element 2: -2 Enter element 3: 3 Enter element 4: -4 Enter element 5: 5 Enter element 6: -6 Enter element 7: 7 Enter element 8: 8 Enter element 9: -9 Enter element 10: 10 The maximum sub array is: 7 8 -9 10 The maximum sub-array sum is: 16
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