问题描述
我认为我会通过编码一些基本的DS和Algos来修改我的概念。经过很大的步伐,我现在有点卡住了,无法识别我的错误。 我在以下代码结果中遇到了细分错误。任何帮助都会很棒!
#include<bits/stdc++.h>
using namespace std;
void merge(int *arr,int s,int m,int e){
int n1 = m-s,n2 = e-m+1;
int L[n1],R[n2];
for(int i=0; i<n1; i++)
L[i] = arr[s+i];
for(int i=0; i<n2; i++)
R[i] = arr[m+i];
int p1 = 0,p2 = 0,k = s;
while(p1<n1 && p2<n1){
if(L[p1] <= R[p2])
arr[k++] = L[p1++];
else
arr[k++] = R[p2++];
}
while(p1<n1)
arr[k++] = L[p1++];
while(p2<n2)
arr[k++] = R[p2++];
return;
}
void mergeSort(int *arr,int e){
if(s>=e) return;
int m = (s+e)/2;
mergeSort(arr,s,m-1);
mergeSort(arr,m,e);
merge(arr,e);
return;
}
int main(){
int n;
cin>>n;
int arr[n];
for(int i=0; i<n; i++)
cin>>arr[i];
mergeSort(arr,n-1);
for(int i=0; i<n; i++)
cout<<arr[i]<<" ";
cout<<endl;
return 0;
}
谢谢!
解决方法
分段错误是因为您有无限递归循环。索引有一些问题,一个错字是您指n2但写了n1。
#include <iostream>
using namespace std;
void merge(int *arr,int s,int m,int e){
int n1 = m-s+1,n2 = e-m;
int L[n1],R[n2];
for(int i=0; i<n1; i++)
L[i] = arr[s+i];
for(int i=0; i<n2; i++)
R[i] = arr[m+i+1];
int p1 = 0,p2 = 0,k = s;
while(p1<n1 && p2<n2){
if(L[p1] <= R[p2])
arr[k++] = L[p1++];
else
arr[k++] = R[p2++];
}
while(p1<n1)
arr[k++] = L[p1++];
while(p2<n2)
arr[k++] = R[p2++];
return;
}
void mergeSort(int *arr,int e){
if(s>=e) return;
int m = (s+e)/2;
mergeSort(arr,s,m);
mergeSort(arr,m+1,e);
merge(arr,m,e);
return;
}
int main() {
int n;
cout << "Select value for N:";
cin>>n;
int arr[n];
cout << "Reading input:";
for(int i=0; i<n; i++)
cin >> arr[i];
cout << "Your input is:" << endl;
for(int i=0; i<n; i++)
cout << arr[i]<<" ";
cout << endl;
cout << "Running merge sort" << endl;
mergeSort(arr,n-1);
cout << "Final array:" << endl;
for(int i=0; i<n; i++)
cout<<arr[i]<<" ";
cout << endl;
return 0;
}