sort function C++ segmentation fault
c++, segmentation-fault, sorting
Solution
In C++, your `compare` predicate must be a strict weak ordering. In particular, `compare(X,X)` must return "false" for any X. In your compare function, if both pairs are identical, you hit the test `(p1.first <= p2.first)` , and return `true`. Therefore, this `compare` predicate does not impose a strict weak ordering, and the result of passing it to `sort` is undefined.
Problem
In this code, for vector size, n >=32767, it gives segmentation fault, but upto 32766, it runs fine. What could be the error? This is full code. ``` #include<cstdio> #include<cstring> #include<cmath> #include<queue> #include<utility> #include<algorithm> #include<sys/time.h> using namespace std; #define MAX 100000 bool compare(pair<int,int> p1,pair<int,int> p2) { if(p1.second < p2.second) return 1; else if(p1.second > p2.second) return 0; if(p1.first <= p2.first) return 1; else return 0; } int main() { freopen("randomin.txt","r",stdin); int n; scanf("%d",&n); vector< pair<int,int> > p(n); for(int i=0;i<n;i++) scanf("%d%d",&p[i].first,&p[i].second); **printf("%d\n",(int)p.max_size()); // prints 536870911** sort(p.begin(),p.begin()+n,compare); //for(int i=0;i<n;i++) //printf("%d %d\n",p[i].first,p[i].second); printf("%.6f\n",(p[n-1].second+p[n-2].second)/(20.0+p[n-1].first+p[n-2].first)); return 0; } ```