Can't find possible run time error using maps

Question

I am getting a segmentation fault somewhere, but since I don't have access to the case tests (this is judged by an auto-judge on a programming contest website) I can't find out where.

#include <iostream>
#include <stdio.h>
#include <map>
#include <algorithm>

using namespace std;

typedef pair<unsigned short int, unsigned short int> par;

int main(){
    int x, y, p, q, a1, b1, a2, b2, val;
    int cont, lin_min, lin_max, col_min, col_max;
    char cmd;
    while((cin >> x >> y >> p) && !(x==0 && y==0 && p==0)){
        cin >> q;
        //Using "getchar ()" to avoid reading line end, because below I'm reading a character
        getchar();
        map<par, int> matriz;
        map<par, int>::iterator it;
        for(int i=0;i<q;i++){
            cin >> cmd;
            //if command 'A' insert in matriz or incremente if already exists
            if(cmd=='A'){
                cin >> val >> a1 >> b1;
                //insert into map (my implementation for sparse matrix)
                matriz[par(a1, b1)]+=val;
            }else 
            //if command 'P' performs a search in the rectangle (a1, b1 to a2, b2)
            if(cmd=='P'){
                cont=0;
                cin >> a1 >> b1 >> a2 >> b2;
                lin_min = min(a1,a2);
                lin_max = max(a1,a2);
                col_min = min(b1,b2);
                col_max = max(b1,b2);
                //traverses the sparse matrix by summing the values that belong to the rectangle
                //I STRONGLY believe that the error is somewhere around here
                for(it=matriz.begin(); it!=matriz.end(); ++it){
                    if((it->first.first>=lin_min && it->first.first<=lin_max)&&
                        (it->first.second>=col_min && it->first.second<=col_max)){
                        cont+=it->second;
                    }
                    if (it->first.first>lin_max && it->first.second>col_max) break;
                }
                cout << cont*p << "\n";
            }
        }
    }
    return 0;
}

Example of input:

2 2 10
7
A 11 1 1
A 4 1 0
A 20 0 0
P 1 0 1 1
A 1 0 1
A 6 1 0
P 0 1 1 0
0 0 0

For two days I have been searching for places where I would have possible invalid memory accesses but I couldn't find or think of any.

What are the possible lines in this code that would cause possible run time errors?

Answer 1

I see a lot of possible improvements in your code, but no reason for runtime error. However on a lot of judge systems I have seen memory limit being displayed as runtime error and I believe this is the case with your code too.

A TIP: try to google binary index tree and nested binary index tree. Google translate is not perfect in translating the statement but I believe this may lead you to a solution that is asymptotically better.

Answer 2

First of all,please try to use typedef in you code, so that it is easy to read. Second i don't see any error in your code and is running fine giving output 150,420 as per the give input . I ran it over many online judge testing platforms and there was no runtime error. TRY IT ON www.ideone.com