本题思路正确,注意点:出现段错误可能原因:
1、数组给小了
2、数组下标超出数组大小了
#include<cstdio>
#include<cstdlib>
#include<string.h>
#include<math.h>
#include<iostream>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<string>
#include<algorithm>
using namespace std;
const int maxn=100010;
int c[maxn],p[maxn];
bool cmp(int a,int b){
return a>b;
}
int main(){
#ifdef ONLINE_JUDGE
#else
freopen("1.txt","r",stdin);
#endif
int nc,np;
long long sum=0;
scanf("%d",&nc);
for(int i=1;i<=nc;i++){
scanf("%d",&c[i]);
}
scanf("%d",&np);
for(int i=1;i<=np;i++){
scanf("%d",&p[i]);
}
sort(c+1,c+nc+1,cmp);
sort(p+1,p+np+1,cmp);
if((c[nc]>=0&&p[1]<=0)||(c[1]<=0&&p[np]>=0)){
printf("0");
return 0;
}
//正数相乘
int m=1,n=1;
while(c[m]>0&&p[n]>0){
sum+=(long long)(c[m]*p[n]);
m++;
n++;
}
while(c[m]>=0&&m<=nc){ //之前遗漏了m<=nc的判断,以致于出现了数组下标越界的情况,报段错误
m++;
}
while(p[n]>=0&&n<=np){ //之前遗漏了n<=np的判断,以致于出现了数组下标越界的情况,报段错误
n++;
}
while(nc>=m&&np>=n){
sum+=(long long)(c[nc]*p[np]);
nc--;
np--;
}
printf("%lld",sum);
return 0;
}
算法笔记中比较简洁明了的写法(值得学习:两个while循环):
#include<cstdio>
#include<cstdlib>
#include<string.h>
#include<math.h>
#include<iostream>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<string>
#include<algorithm>
using namespace std;
const int maxn=100010;
int c[maxn],p[maxn];
bool cmp(int a,int b){
return a>b;
}
int main(){
#ifdef ONLINE_JUDGE
#else
freopen("1.txt","r",stdin);
#endif
int nc,np;
long long sum=0;
scanf("%d",&nc);
for(int i=1;i<=nc;i++){
scanf("%d",&c[i]);
}
scanf("%d",&np);
for(int i=1;i<=np;i++){
scanf("%d",&p[i]);
}
sort(c+1,c+nc+1,cmp);
sort(p+1,p+np+1,cmp);
int m=1,n=1;
while(m<=nc&&n<=np&&c[m]>0&&p[n]>0){
sum+=c[m]*p[n];
m++;
n++;
}
m=nc,n=np;
while(m>=1&&n>=1&&c[m]<0&&p[n]<0){
sum+=c[m]*p[n];
m--;
n--;
}
printf("%lld",sum);
return 0;
}