SRM624 Div1 Easy in C++

BuildingHeights.cpp

#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <typeinfo>
#include <fstream>

using namespace std;

class BuildingHeights {
    public:
    int minimum(vector<int> heights) {
    	int N = heights.size();
        sort(heights.begin(), heights.end());

        int sums[heights.size() + 1];
        sums[0] = 0;
        for (int i = 0; i < N; ++i){
            sums[i+1] = sums[i] + heights[i];
        }

        int result = 0;
        for (int n = 2; n <= N; ++n){
            int mini = 2147483647; //INT_MAXにしたい
            for (int l = 0; l <= N - n; ++l){
            	mini = min(mini, heights[l + n - 1] * n - (sums[l + n] - sums[l]));
            }
            result ^= mini;
        }
        return result;
    }

};